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Genetic engineering – Wikipedia

Genetic engineering, also called genetic modification or genetic manipulation, is the direct manipulation of an organism’s genes using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. As well as inserting genes, the process can be used to remove, or “knock out”, genes. The new DNA can be inserted randomly, or targeted to a specific part of the genome.

An organism that is generated through genetic engineering is considered to be genetically modified (GM) and the resulting entity is a genetically modified organism (GMO). The first GMO was a bacterium generated by Herbert Boyer and Stanley Cohen in 1973. Rudolf Jaenisch created the first GM animal when he inserted foreign DNA into a mouse in 1974. The first company to focus on genetic engineering, Genentech, was founded in 1976 and started the production of human proteins. Genetically engineered human insulin was produced in 1978 and insulin-producing bacteria were commercialised in 1982. Genetically modified food has been sold since 1994, with the release of the Flavr Savr tomato. The Flavr Savr was engineered to have a longer shelf life, but most current GM crops are modified to increase resistance to insects and herbicides. GloFish, the first GMO designed as a pet, was sold in the United States in December 2003. In 2016 salmon modified with a growth hormone were sold.

Genetic engineering has been applied in numerous fields including research, medicine, industrial biotechnology and agriculture. In research GMOs are used to study gene function and expression through loss of function, gain of function, tracking and expression experiments. By knocking out genes responsible for certain conditions it is possible to create animal model organisms of human diseases. As well as producing hormones, vaccines and other drugs genetic engineering has the potential to cure genetic diseases through gene therapy. The same techniques that are used to produce drugs can also have industrial applications such as producing enzymes for laundry detergent, cheeses and other products.

The rise of commercialised genetically modified crops has provided economic benefit to farmers in many different countries, but has also been the source of most of the controversy surrounding the technology. This has been present since its early use; the first field trials were destroyed by anti-GM activists. Although there is a scientific consensus that currently available food derived from GM crops poses no greater risk to human health than conventional food, GM food safety is a leading concern with critics. Gene flow, impact on non-target organisms, control of the food supply and intellectual property rights have also been raised as potential issues. These concerns have led to the development of a regulatory framework, which started in 1975. It has led to an international treaty, the Cartagena Protocol on Biosafety, that was adopted in 2000. Individual countries have developed their own regulatory systems regarding GMOs, with the most marked differences occurring between the US and Europe.

Genetic engineering is a process that alters the genetic structure of an organism by either removing or introducing DNA. Unlike traditional animal and plant breeding, which involves doing multiple crosses and then selecting for the organism with the desired phenotype, genetic engineering takes the gene directly from one organism and inserts it in the other. This is much faster, can be used to insert any genes from any organism (even ones from different domains) and prevents other undesirable genes from also being added.[3]

Genetic engineering could potentially fix severe genetic disorders in humans by replacing the defective gene with a functioning one.[4] It is an important tool in research that allows the function of specific genes to be studied.[5] Drugs, vaccines and other products have been harvested from organisms engineered to produce them.[6] Crops have been developed that aid food security by increasing yield, nutritional value and tolerance to environmental stresses.[7]

The DNA can be introduced directly into the host organism or into a cell that is then fused or hybridised with the host.[8] This relies on recombinant nucleic acid techniques to form new combinations of heritable genetic material followed by the incorporation of that material either indirectly through a vector system or directly through micro-injection, macro-injection or micro-encapsulation.[9]

Genetic engineering does not normally include traditional breeding, in vitro fertilisation, induction of polyploidy, mutagenesis and cell fusion techniques that do not use recombinant nucleic acids or a genetically modified organism in the process.[8] However, some broad definitions of genetic engineering include selective breeding.[9] Cloning and stem cell research, although not considered genetic engineering,[10] are closely related and genetic engineering can be used within them.[11] Synthetic biology is an emerging discipline that takes genetic engineering a step further by introducing artificially synthesised material into an organism.[12]

Plants, animals or micro organisms that have been changed through genetic engineering are termed genetically modified organisms or GMOs.[13] If genetic material from another species is added to the host, the resulting organism is called transgenic. If genetic material from the same species or a species that can naturally breed with the host is used the resulting organism is called cisgenic.[14] If genetic engineering is used to remove genetic material from the target organism the resulting organism is termed a knockout organism.[15] In Europe genetic modification is synonymous with genetic engineering while within the United States of America and Canada genetic modification can also be used to refer to more conventional breeding methods.[16][17][18]

Humans have altered the genomes of species for thousands of years through selective breeding, or artificial selection[19]:1[20]:1 as contrasted with natural selection. More recently, mutation breeding has used exposure to chemicals or radiation to produce a high frequency of random mutations, for selective breeding purposes. Genetic engineering as the direct manipulation of DNA by humans outside breeding and mutations has only existed since the 1970s. The term “genetic engineering” was first coined by Jack Williamson in his science fiction novel Dragon’s Island, published in 1951[21] one year before DNA’s role in heredity was confirmed by Alfred Hershey and Martha Chase,[22] and two years before James Watson and Francis Crick showed that the DNA molecule has a double-helix structure though the general concept of direct genetic manipulation was explored in rudimentary form in Stanley G. Weinbaum’s 1936 science fiction story Proteus Island.[23][24]

In 1972, Paul Berg created the first recombinant DNA molecules by combining DNA from the monkey virus SV40 with that of the lambda virus.[25] In 1973 Herbert Boyer and Stanley Cohen created the first transgenic organism by inserting antibiotic resistance genes into the plasmid of an Escherichia coli bacterium.[26][27] A year later Rudolf Jaenisch created a transgenic mouse by introducing foreign DNA into its embryo, making it the worlds first transgenic animal[28] These achievements led to concerns in the scientific community about potential risks from genetic engineering, which were first discussed in depth at the Asilomar Conference in 1975. One of the main recommendations from this meeting was that government oversight of recombinant DNA research should be established until the technology was deemed safe.[29][30]

In 1976 Genentech, the first genetic engineering company, was founded by Herbert Boyer and Robert Swanson and a year later the company produced a human protein (somatostatin) in E.coli. Genentech announced the production of genetically engineered human insulin in 1978.[31] In 1980, the U.S. Supreme Court in the Diamond v. Chakrabarty case ruled that genetically altered life could be patented.[32] The insulin produced by bacteria was approved for release by the Food and Drug Administration (FDA) in 1982.[33]

In 1983, a biotech company, Advanced Genetic Sciences (AGS) applied for U.S. government authorisation to perform field tests with the ice-minus strain of Pseudomonas syringae to protect crops from frost, but environmental groups and protestors delayed the field tests for four years with legal challenges.[34] In 1987, the ice-minus strain of P. syringae became the first genetically modified organism (GMO) to be released into the environment[35] when a strawberry field and a potato field in California were sprayed with it.[36] Both test fields were attacked by activist groups the night before the tests occurred: “The world’s first trial site attracted the world’s first field trasher”.[35]

The first field trials of genetically engineered plants occurred in France and the US in 1986, tobacco plants were engineered to be resistant to herbicides.[37] The Peoples Republic of China was the first country to commercialise transgenic plants, introducing a virus-resistant tobacco in 1992.[38] In 1994 Calgene attained approval to commercially release the first genetically modified food, the Flavr Savr, a tomato engineered to have a longer shelf life.[39] In 1994, the European Union approved tobacco engineered to be resistant to the herbicide bromoxynil, making it the first genetically engineered crop commercialised in Europe.[40] In 1995, Bt Potato was approved safe by the Environmental Protection Agency, after having been approved by the FDA, making it the first pesticide producing crop to be approved in the US.[41] In 2009 11 transgenic crops were grown commercially in 25 countries, the largest of which by area grown were the US, Brazil, Argentina, India, Canada, China, Paraguay and South Africa.[42]

In 2010, scientists at the J. Craig Venter Institute created the first synthetic genome and inserted it into an empty bacterial cell. The resulting bacterium, named Mycoplasma laboratorium, could replicate and produce proteins.[43][44] Four years later this was taken a step further when a bacterium was developed that replicated a plasmid containing a unique base pair, creating the first organism engineered to use an expanded genetic alphabet.[45][46] In 2012, Jennifer Doudna and Emmanuelle Charpentier collaborated to develop the CRISPR/Cas9 system,[47][48] a technique which can be used to easily and specifically alter the genome of almost any organism.[49]

Creating a GMO is a multi-step process. Genetic engineers must first choose what gene they wish to insert into the organism. This is driven by what the aim is for the resultant organism and is built on earlier research. Genetic screens can be carried out to determine potential genes and further tests then used to identify the best candidates. The development of microarrays, transcriptomics and genome sequencing has made it much easier to find suitable genes.[50] Luck also plays its part; the round-up ready gene was discovered after scientists noticed a bacterium thriving in the presence of the herbicide.[51]

The next step is to isolate the candidate gene. The cell containing the gene is opened and the DNA is purified.[52] The gene is separated by using restriction enzymes to cut the DNA into fragments[53] or polymerase chain reaction (PCR) to amplify up the gene segment.[54] These segments can then be extracted through gel electrophoresis. If the chosen gene or the donor organism’s genome has been well studied it may already be accessible from a genetic library. If the DNA sequence is known, but no copies of the gene are available, it can also be artificially synthesised.[55] Once isolated the gene is ligated into a plasmid that is then inserted into a bacterium. The plasmid is replicated when the bacteria divide, ensuring unlimited copies of the gene are available.[56]

Before the gene is inserted into the target organism it must be combined with other genetic elements. These include a promoter and terminator region, which initiate and end transcription. A selectable marker gene is added, which in most cases confers antibiotic resistance, so researchers can easily determine which cells have been successfully transformed. The gene can also be modified at this stage for better expression or effectiveness. These manipulations are carried out using recombinant DNA techniques, such as restriction digests, ligations and molecular cloning.[57]

There are a number of techniques available for inserting the gene into the host genome. Some bacteria can naturally take up foreign DNA. This ability can be induced in other bacteria via stress (e.g. thermal or electric shock), which increases the cell membrane’s permeability to DNA; up-taken DNA can either integrate with the genome or exist as extrachromosomal DNA. DNA is generally inserted into animal cells using microinjection, where it can be injected through the cell’s nuclear envelope directly into the nucleus, or through the use of viral vectors.[58]

In plants the DNA is often inserted using Agrobacterium-mediated recombination,[59] taking advantage of the Agrobacteriums T-DNA sequence that allows natural insertion of genetic material into plant cells.[60] Other methods include biolistics, where particles of gold or tungsten are coated with DNA and then shot into young plant cells,[61] and electroporation, which involves using an electric shock to make the cell membrane permeable to plasmid DNA. Due to the damage caused to the cells and DNA the transformation efficiency of biolistics and electroporation is lower than agrobacterial transformation and microinjection.[62]

As only a single cell is transformed with genetic material, the organism must be regenerated from that single cell. In plants this is accomplished through the use of tissue c ulture.[63][64] In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells.[65] Bacteria consist of a single cell and reproduce clonally so regeneration is not necessary. Selectable markers are used to easily differentiate transformed from untransformed cells. These markers are usually present in the transgenic organism, although a number of strategies have been developed that can remove the selectable marker from the mature transgenic plant.[66]

Further testing using PCR, Southern hybridization, and DNA sequencing is conducted to confirm that an organism contains the new gene.[67] These tests can also confirm the chromosomal location and copy number of the inserted gene. The presence of the gene does not guarantee it will be expressed at appropriate levels in the target tissue so methods that look for and measure the gene products (RNA and protein) are also used. These include northern hybridisation, quantitative RT-PCR, Western blot, immunofluorescence, ELISA and phenotypic analysis.[68]

The new genetic material can be inserted randomly within the host genome or targeted to a specific location. The technique of gene targeting uses homologous recombination to make desired changes to a specific endogenous gene. This tends to occur at a relatively low frequency in plants and animals and generally requires the use of selectable markers. The frequency of gene targeting can be greatly enhanced through genome editing. Genome editing uses artificially engineered nucleases that create specific double-stranded breaks at desired locations in the genome, and use the cells endogenous mechanisms to repair the induced break by the natural processes of homologous recombination and nonhomologous end-joining. There are four families of engineered nucleases: meganucleases,[69][70] zinc finger nucleases,[71][72] transcription activator-like effector nucleases (TALENs),[73][74] and the Cas9-guideRNA system (adapted from CRISPR).[75][76] TALEN and CRISPR are the two most commonly used and each has its own advantages.[77] TALENs have greater target specificity, while CRISPR is easier to design and more efficient.[77] In addition to enhancing gene targeting, engineered nucleases can be used to introduce mutations at endogenous genes that generate a gene knockout.[78][79]

Genetic engineering has applications in medicine, research, industry and agriculture and can be used on a wide range of plants, animals and micro organisms. Bacteria, the first organisms to be genetically modified, can have plasmid DNA inserted containing new genes that code for medicines or enzymes that process food and other substrates.[80][81] Plants have been modified for insect protection, herbicide resistance, virus resistance, enhanced nutrition, tolerance to environmental pressures and the production of edible vaccines.[82] Most commercialised GMOs are insect resistant or herbicide tolerant crop plants.[83] Genetically modified animals have been used for research, model animals and the production of agricultural or pharmaceutical products. The genetically modified animals include animals with genes knocked out, increased susceptibility to disease, hormones for extra growth and the ability to express proteins in their milk.[84]

Genetic engineering has many applications to medicine that include the manufacturing of drugs, creation of model animals that mimic human conditions and gene therapy. One of the earliest uses of genetic engineering was to mass-produce human insulin in bacteria.[31] This application has now been applied to, human growth hormones, follicle stimulating hormones (for treating infertility), human albumin, monoclonal antibodies, antihemophilic factors, vaccines and many other drugs.[85][86] Mouse hybridomas, cells fused together to create monoclonal antibodies, have been adapted through genetic engineering to create human monoclonal antibodies.[87] In 2017, genetic engineering of chimeric antigen receptors on a patient’s own T-cells was approved by the U.S. FDA as a treatment for the cancer acute lymphoblastic leukemia. Genetically engineered viruses are being developed that can still confer immunity, but lack the infectious sequences.[88]

Genetic engineering is also used to create animal models of human diseases. Genetically modified mice are the most common genetically engineered animal model.[89] They have been used to study and model cancer (the oncomouse), obesity, heart disease, diabetes, arthritis, substance abuse, anxiety, aging and Parkinson disease.[90] Potential cures can be tested against these mouse models. Also genetically modified pigs have been bred with the aim of increasing the success of pig to human organ transplantation.[91]

Gene therapy is the genetic engineering of humans, generally by replacing defective genes with effective ones. Clinical research using somatic gene therapy has been conducted with several diseases, including X-linked SCID,[92] chronic lymphocytic leukemia (CLL),[93][94] and Parkinson’s disease.[95] In 2012, Alipogene tiparvovec became the first gene therapy treatment to be approved for clinical use.[96][97] In 2015 a virus was used to insert a healthy gene into the skin cells of a boy suffering from a rare skin disease, epidermolysis bullosa, in order to grow, and then graft healthy skin onto 80 percent of the boy’s body which was affected by the illness.[98]

Germline gene therapy would result in any change being inheritable, which has raised concerns within the scientific community.[99][100] In 2015, CRISPR was used to edit the DNA of non-viable human embryos,[101][102] leading scientists of major world academies to call for a moratorium on inheritable human genome edits.[103] There are also concerns that the technology could be used not just for treatment, but for enhancement, modification or alteration of a human beings’ appearance, adaptability, intelligence, character or behavior.[104] The distinction between cure and enhancement can also be difficult to establish.[105] In November 2018, He Jiankui announced that he had edited the genomes of two human embryos, to attempt to disable the CCR5 gene, which codes for a receptor that HIV uses to enter cells. He said that twin girls, Lulu and Nana, had been born a few weeks earlier. He said that the girls still carried functional copies of CCR5 along with disabled CCR5 (mosaicism) and were still vulnerable to HIV. The work was widely condemned as unethical, dangerous, and premature.[106]

Researchers are altering the genome of pigs to induce the growth of human organs to be used in transplants. Scientists are creating “gene drives”, changing the genomes of mosquitoes to make them immune to malaria, and then looking to spread the genetically altered mosquitoes throughout the mosquito population in the hopes of eliminating the disease.[107]

Genetic engineering is an important tool for natural scientists, with the creation of transgenic organisms one of the most important tools for analysis of gene function.[108] Genes and other genetic information from a wide range of organisms can be inserted into bacteria for storage and modification, creating genetically modified bacteria in the process. Bacteria are cheap, easy to grow, clonal, multiply quickly, relatively easy to transform and can be stored at -80C almost indefinitely. Once a gene is isolated it can be stored inside the bacteria providing an unlimited supply for research.[109]Organisms are genetically engineered to discover the functions of certain genes. This could be the effect on the phenotype of the organism, where the gene is expressed or what other genes it interacts with. These experiments generally involve loss of function, gain of function, tracking and expression.

Organisms can have their cells transformed with a gene coding for a useful protein, such as an enzyme, so that they will overexpress the desired protein. Mass quantities of the protein can then be manufactured by growing the transformed organism in bioreactor equipment using industrial fermentation, and then purifying the protein.[113] Some genes do not work well in bacteria, so yeast, insect cells or mammalians cells can also be used.[114] These techniques are used to produce medicines such as insulin, human growth hormone, and vaccines, supplements such as tryptophan, aid in the production of food (chymosin in cheese making) and fuels.[115] Other applications with genetically engineered bacteria could involve making them perform tasks outside their natural cycle, such as making biofuels,[116] cleaning up oil spills, carbon and other toxic waste[117] and detecting arsenic in drinking water.[118] Certain genetically modified microbes can also be used in biomining and bioremediation, due to their ability to extract heavy metals from their environment and incorporate them into compounds that are more easily recoverable.[119]

In materials science, a genetically modified virus has been used in a research laboratory as a scaffold for assembling a more environmentally friendly lithium-ion battery.[120][121] Bacteria have also been engineered to function as sensors by expressing a fluorescent protein under certain environmental conditions.[122]

One of the best-known and controversial applications of genetic engineering is the creation and use of genetically modified crops or genetically modified livestock to produce genetically modified food. Crops have been developed to increase production, increase tolerance to abiotic stresses, alter the composition of the food, or to produce novel products.[124]

The first crops to be released commercially on a large scale provided protection from insect pests or tolerance to herbicides. Fungal and virus resistant crops have also been developed or are in development.[125][126] This make the insect and weed management of crops easier and can indirectly increase crop yield.[127][128] GM crops that directly improve yield by accelerating growth or making the plant more hardy (by improving salt, cold or drought tolerance) are also under development.[129] In 2016 Salmon have been genetically modified with growth hormones to reach normal adult size much faster.[130]

GMOs have been developed that modify the quality of produce by increasing the nutritional value or providing more industrially useful qualities or quantities.[129] The Amflora potato produces a more industrially useful blend of starches. Soybeans and canola have been genetically modified to produce more healthy oils.[131][132] The first commercialised GM food was a tomato that had delayed ripening, increasing its shelf life.[133]

Plants and animals have been engineered to produce materials they do not normally make. Pharming uses crops and animals as bioreactors to produce vaccines, drug intermediates, or the drugs themselves; the useful product is purified from the harvest and then used in the standard pharmaceutical production process.[134] Cows and goats have been engineered to express drugs and other proteins in their milk, and in 2009 the FDA approved a drug produced in goat milk.[135][136]

Genetic engineering has potential applications in conservation and natural area management. Gene transfer through viral vectors has been proposed as a means of controlling invasive species as well as vaccinating threatened fauna from disease.[137] Transgenic trees have been suggested as a way to confer resistance to pathogens in wild populations.[138] With the increasing risks of maladaptation in organisms as a result of climate change and other perturbations, facilitated adaptation through gene tweaking could be one solution to reducing extinction risks.[139] Applications of genetic engineering in conservation are thus far mostly theoretical and have yet to be put into practice.

Genetic engineering is also being used to create microbial art.[140] Some bacteria have been genetically engineered to create black and white photographs.[141] Novelty items such as lavender-colored carnations,[142] blue roses,[143] and glowing fish[144][145] have also been produced through genetic engineering.

The regulation of genetic engineering concerns the approaches taken by governments to assess and manage the risks associated with the development and release of GMOs. The development of a regulatory framework began in 1975, at Asilomar, California.[146] The Asilomar meeting recommended a set of voluntary guidelines regarding the use of recombinant technology.[29] As the technology improved the US established a committee at the Office of Science and Technology,[147] which assigned regulatory approval of GM food to the USDA, FDA and EPA.[148] The Cartagena Protocol on Biosafety, an international treaty that governs the transfer, handling, and use of GMOs,[149] was adopted on 29 January 2000.[150] One hundred and fifty-seven countries are members of the Protocol and many use it as a reference point for their own regulations.[151]

The legal and regulatory status of GM foods varies by country, with some nations banning or restricting them, and others permitting them with widely differing degrees of regulation.[152][153][154][155] Some countries allow the import of GM food with authorisation, but either do not allow its cultivation (Russia, Norway, Israel) or have provisions for cultivation even though no GM products are yet produced (Japan, South Korea). Most countries that do not allow GMO cultivation do permit research.[156] Some of the most marked differences occurring between the US and Europe. The US policy focuses on the product (not the process), only looks at verifiable scientific risks and uses the concept of substantial equivalence.[157] The European Union by contrast has possibly the most stringent GMO regulations in the world.[158] All GMOs, along with irradiated food, are considered “new food” and subject to extensive, case-by-case, science-based food evaluation by the European Food Safety Authority. The criteria for authorisation fall in four broad categories: “safety,” “freedom of choice,” “labelling,” and “traceability.”[159] The level of regulation in other countries that cultivate GMOs lie in between Europe and the United States.

One of the key issues concerning regulators is whether GM products should be labeled. The European Commission says that mandatory labeling and traceability are needed to allow for informed choice, avoid potential false advertising[170] and facilitate the withdrawal of products if adverse effects on health or the environment are discovered.[171] The American Medical Association[172] and the American Association for the Advancement of Science[173] say that absent scientific evidence of harm even voluntary labeling is misleading and will falsely alarm consumers. Labeling of GMO products in the marketplace is required in 64 countries.[174] Labeling can be mandatory up to a threshold GM content level (which varies between countries) or voluntary. In Canada and the US labeling of GM food is voluntary,[175] while in Europe all food (including processed food) or feed which contains greater than 0.9% of approved GMOs must be labelled.[158]

Critics have objected to the use of genetic engineering on several grounds, that include ethical, ecological and economic concerns. Many of these concerns involve GM crops and whether food produced from them is safe and what impact growing them will have on the environment. These controversies have led to litigation, international trade disputes, and protests, and to restrictive regulation of commercial products in some countries.[176]

Accusations that scientists are “playing God” and other religious issues have been ascribed to the technology from the beginning.[177] Other ethical issues raised include the patenting of life,[178] the use of intellectual property rights,[179] the level of labeling on products,[180][181] control of the food supply[182] and the objectivity of the regulatory process.[183] Although doubts have been raised,[184] economically most studies have found growing GM crops to be beneficial to farmers.[185][186][187]

Gene flow between GM crops and compatible plants, along with increased use of selective herbicides, can increase the risk of “superweeds” developing.[188] Other environmental concerns involve potential impacts on non-target organisms, including soil microbes,[189] and an increase in secondary and resistant insect pests.[190][191] Many of the environmental impacts regarding GM crops may take many years to be understood and are also evident in conventional agriculture practices.[189][192] With the commercialisation of genetically modified fish there are concerns over what the environmental consequences will be if they escape.[193]

There are three main concerns over the safety of genetically modified food: whether they may provoke an allergic reaction; whether the genes could transfer from the food into human cells; and whether the genes not approved for human consumption could outcross to other crops.[194] There is a scientific consensus[195][196][197][198] that currently available food derived from GM crops poses no greater risk to human health than conventional food,[199][200][201][202][203] but that each GM food needs to be tested on a case-by-case basis before introduction.[204][205][206] Nonetheless, members of the public are much less likely than scientists to perceive GM foods as safe.[207][208][209][210]

Genetic engineering features in many science fiction stories.[211] Frank Herbert’s novel The White Plague described the deliberate use of genetic engineering to create a pathogen which specifically killed women.[211] Another of Herbert’s creations, the Dune series of novels, uses genetic engineering to create the powerful but despised Tleilaxu.[212] Films such as The Island and Blade Runner bring the engineered creature to confront the person who created it or the being it was cloned from. Few films have informed audiences about genetic engineering, with the exception of the 1978 The Boys from Brazil and the 1993 Jurassic Park, both of which made use of a lesson, a demonstration, and a clip of scientific film.[213][214] Genetic engineering methods are weakly represented in film; Michael Clark, writing for The Wellcome Trust, calls the portrayal of genetic engineering and biotechnology “seriously distorted”[214] in films such as The 6th Day. In Clark’s view, the biotechnology is typically “given fantastic but visually arresting forms” while the science is either relegated to the background or fictionalised to suit a young audience.[214]

The literature about Biodiversity and the GE food/feed consumption has sometimes resulted in animated debate regarding the suitability of the experimental designs, the choice of the statistical methods or the public accessibility of data. Such debate, even if positive and part of the natural process of review by the scientific community, has frequently been distorted by the media and often used politically and inappropriately in anti-GE crops campaigns.

Panchin AY, Tuzhikov AI (March 2017). “Published GMO studies find no evidence of harm when corrected for multiple comparisons”. Critical Reviews in Biotechnology. 37 (2): 213217. doi:10.3109/07388551.2015.1130684. PMID26767435. Here, we show that a number of articles some of which have strongly and negatively influenced the public opinion on GM crops and even provoked political actions, such as GMO embargo, share common flaws in the statistical evaluation of the data. Having accounted for these flaws, we conclude that the data presented in these articles does not provide any substantial evidence of GMO harm.

The presented articles suggesting possible harm of GMOs received high public attention. However, despite their claims, they actually weaken the evidence for the harm and lack of substantial equivalency of studied GMOs. We emphasize that with over 1783 published articles on GMOs over the last 10 years it is expected that some of them should have reported undesired differences between GMOs and conventional crops even if no such differences exist in reality.and

Yang YT, Chen B (April 2016). “Governing GMOs in the USA: science, law and public health”. Journal of the Science of Food and Agriculture. 96 (6): 18515. doi:10.1002/jsfa.7523. PMID26536836. It is therefore not surprising that efforts to require labeling and to ban GMOs have been a growing political issue in the USA (citing Domingo and Bordonaba, 2011).

Overall, a broad scientific consensus holds that currently marketed GM food poses no greater risk than conventional food… Major national and international science and medical associations have stated that no adverse human health effects related to GMO food have been reported or substantiated in peer-reviewed literature to date.

Despite various concerns, today, the American Association for the Advancement of Science, the World Health Organization, and many independent international science organizations agree that GMOs are just as safe as other foods. Compared with conventional breeding techniques, genetic engineering is far more precise and, in most cases, less likely to create an unexpected outcome.

GM foods currently available on the international market have passed safety assessments and are not likely to present risks for human health. In addition, no effects on human health have been shown as a result of the consumption of such foods by the general population in the countries where they have been approved. Continuous application of safety assessments based on the Codex Alimentarius principles and, where appropriate, adequate post market monitoring, should form the basis for ensuring the safety of GM foods.

“Genetically modified foods and health: a second interim statement” (PDF). British Medical Association. March 2004. Retrieved 21 March 2016. In our view, the potential for GM foods to cause harmful health effects is very small and many of the concerns expressed apply with equal vigour to conventionally derived foods. However, safety concerns cannot, as yet, be dismissed completely on the basis of information currently available.

When seeking to optimise the balance between benefits and risks, it is prudent to err on the side of caution and, above all, learn from accumulating knowledge and experience. Any new technology such as genetic modification must be examined for possible benefits and risks to human health and the environment. As with all novel foods, safety assessments in relation to GM foods must be made on a case-by-case basis.

Members of the GM jury project were briefed on various aspects of genetic modification by a diverse group of acknowledged experts in the relevant subjects. The GM jury reached the conclusion that the sale of GM foods currently available should be halted and the moratorium on commercial growth of GM crops should be continued. These conclusions were based on the precautionary principle and lack of evidence of any benefit. The Jury expressed concern over the impact of GM crops on farming, the environment, food safety and other potential health effects.

The Royal Society review (2002) concluded that the risks to human health associated with the use of specific viral DNA sequences in GM plants are negligible, and while calling for caution in the introduction of potential allergens into food crops, stressed the absence of evidence that commercially available GM foods cause clinical allergic manifestations. The BMA shares the view that that there is no robust evidence to prove that GM foods are unsafe but we endorse the call for further research and surveillance to provide convincing evidence of safety and benefit.

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Genetic engineering – Wikipedia

genetic engineering | Definition, Process, & Uses …

Genetic engineering, the artificial manipulation, modification, and recombination of DNA or other nucleic acid molecules in order to modify an organism or population of organisms.

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origins of agriculture: Genetic engineering

The application of genetics to agriculture since World War II has resulted in substantial increases in the production of many crops. This has been most notable in hybrid strains of maize and grain sorghum. At the same time, crossbreeding has resulted in much

The term genetic engineering initially referred to various techniques used for the modification or manipulation of organisms through the processes of heredity and reproduction. As such, the term embraced both artificial selection and all the interventions of biomedical techniques, among them artificial insemination, in vitro fertilization (e.g., test-tube babies), cloning, and gene manipulation. In the latter part of the 20th century, however, the term came to refer more specifically to methods of recombinant DNA technology (or gene cloning), in which DNA molecules from two or more sources are combined either within cells or in vitro and are then inserted into host organisms in which they are able to propagate.

The possibility for recombinant DNA technology emerged with the discovery of restriction enzymes in 1968 by Swiss microbiologist Werner Arber. The following year American microbiologist Hamilton O. Smith purified so-called type II restriction enzymes, which were found to be essential to genetic engineering for their ability to cleave a specific site within the DNA (as opposed to type I restriction enzymes, which cleave DNA at random sites). Drawing on Smiths work, American molecular biologist Daniel Nathans helped advance the technique of DNA recombination in 197071 and demonstrated that type II enzymes could be useful in genetic studies. Genetic engineering based on recombination was pioneered in 1973 by American biochemists Stanley N. Cohen and Herbert W. Boyer, who were among the first to cut DNA into fragments, rejoin different fragments, and insert the new genes into E. coli bacteria, which then reproduced.

Most recombinant DNA technology involves the insertion of foreign genes into the plasmids of common laboratory strains of bacteria. Plasmids are small rings of DNA; they are not part of the bacteriums chromosome (the main repository of the organisms genetic information). Nonetheless, they are capable of directing protein synthesis, and, like chromosomal DNA, they are reproduced and passed on to the bacteriums progeny. Thus, by incorporating foreign DNA (for example, a mammalian gene) into a bacterium, researchers can obtain an almost limitless number of copies of the inserted gene. Furthermore, if the inserted gene is operative (i.e., if it directs protein synthesis), the modified bacterium will produce the protein specified by the foreign DNA.

A subsequent generation of genetic engineering techniques that emerged in the early 21st century centred on gene editing. Gene editing, based on a technology known as CRISPR-Cas9, allows researchers to customize a living organisms genetic sequence by making very specific changes to its DNA. Gene editing has a wide array of applications, being used for the genetic modification of crop plants and livestock and of laboratory model organisms (e.g., mice). The correction of genetic errors associated with disease in animals suggests that gene editing has potential applications in gene therapy for humans.

Genetic engineering has advanced the understanding of many theoretical and practical aspects of gene function and organization. Through recombinant DNA techniques, bacteria have been created that are capable of synthesizing human insulin, human growth hormone, alpha interferon, a hepatitis B vaccine, and other medically useful substances. Plants may be genetically adjusted to enable them to fix nitrogen, and genetic diseases can possibly be corrected by replacing dysfunctional genes with normally functioning genes. Nevertheless, special concern has been focused on such achievements for fear that they might result in the introduction of unfavourable and possibly dangerous traits into microorganisms that were previously free of theme.g., resistance to antibiotics, production of toxins, or a tendency to cause disease. Likewise, the application of gene editing in humans has raised ethical concerns, particularly regarding its potential use to alter traits such as intelligence and beauty.

In 1980 the new microorganisms created by recombinant DNA research were deemed patentable, and in 1986 the U.S. Department of Agriculture approved the sale of the first living genetically altered organisma virus, used as a pseudorabies vaccine, from which a single gene had been cut. Since then several hundred patents have been awarded for genetically altered bacteria and plants. Patents on genetically engineered and genetically modified organisms, particularly crops and other foods, however, were a contentious issue, and they remained so into the first part of the 21st century.

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genetic engineering | Definition, Process, & Uses …

Pros and Cons of Genetic Engineering – HRF

Manipulation of genes in natural organisms, such as plants, animals, and even humans, is considered genetic engineering. This is done using a variety of different techniques like molecular cloning. These processes can cause dramatic changes in the natural makeup and characteristic of the organism. There are benefits and risks associated with genetic engineering, just like most other scientific practices.

Genetic engineering offers benefits such as:

1. Better Flavor, Growth Rate and NutritionCrops like potatoes, soybeans and tomatoes are now sometimes genetically engineered in order to improve size, crop yield, and nutritional values of the plants. These genetically engineered crops also possess the ability to grow in lands that would normally not be suitable for cultivation.

2. Pest-resistant Crops and Extended Shelf LifeEngineered seeds can resist pests and having a better chance at survival in harsh weather. Biotechnology could be in increasing the shelf life of many foods.

3. Genetic Alteration to Supply New FoodsGenetic engineering can also be used in producing completely new substances like proteins or other nutrients in food. This may up the benefits they have for medical uses.

4. Modification of the Human DNAGenes that are responsible for unique and desirable qualities in the human DNA can be exposed and introduced into the genes of another person. This changes the structural elements of a persons DNA. The effects of this are not know.

The following are the issues that genetic engineering can trigger:

1. May Hamper Nutritional ValueGenetic engineering on food also includes the infectivity of genes in root crops. These crops might supersede the natural weeds. These can be dangerous for the natural plants. Unpleasant genetic mutations could result to an increased allergy occurrence of the crop. Some people believe that this science on foods can hamper the nutrients contained by the crops although their appearance and taste were enhanced.

2. May Introduce Risky PathogensHorizontal gene shift could give increase to other pathogens. While it increases the immunity against diseases among the plants, the resistant genes can be transmitted to harmful pathogens.

3. May Result to Genetic ProblemsGene therapy on humans can end to some side effects. While relieving one problem, the treatment may cause the onset of another issue. As a single cell is liable for various characteristics, the cell isolation process will be responsible for one trait will be complicated.

4. Unfavorable to Genetic DiversityGenetic engineering can affect the diversity among the individuals. Cloning might be unfavorable to individualism. Furthermore, such process might not be affordable for poor. Hence, it makes the gene therapy impossible for an average person.

Genetic engineering might work excellently but after all, it is a kind of process that manipulates the natural. This is altering something which has not been created originally by humans. What can you say about this?

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Pros and Cons of Genetic Engineering – HRF

Gene therapy – Wikipedia

In the medicine field, gene therapy (also called human gene transfer) is the therapeutic delivery of nucleic acid into a patient’s cells as a drug to treat disease.[1][2] The first attempt at modifying human DNA was performed in 1980 by Martin Cline, but the first successful nuclear gene transfer in humans, approved by the National Institutes of Health, was performed in May 1989.[3] The first therapeutic use of gene transfer as well as the first direct insertion of human DNA into the nuclear genome was performed by French Anderson in a trial starting in September 1990.

Between 1989 and February 2016, over 2,300 clinical trials were conducted, with more than half of them in phase I.[4]

Not all medical procedures that introduce alterations to a patient’s genetic makeup can be considered gene therapy. Bone marrow transplantation and organ transplants in general have been found to introduce foreign DNA into patients.[5] Gene therapy is defined by the precision of the procedure and the intention of direct therapeutic effect.

Gene therapy was conceptualized in 1972, by authors who urged caution before commencing human gene therapy studies.

The first attempt, an unsuccessful one, at gene therapy (as well as the first case of medical transfer of foreign genes into humans not counting organ transplantation) was performed by Martin Cline on 10 July 1980.[6][7] Cline claimed that one of the genes in his patients was active six months later, though he never published this data or had it verified[8] and even if he is correct, it’s unlikely it produced any significant beneficial effects treating beta-thalassemia.

After extensive research on animals throughout the 1980s and a 1989 bacterial gene tagging trial on humans, the first gene therapy widely accepted as a success was demonstrated in a trial that started on 14 September 1990, when Ashi DeSilva was treated for ADA-SCID.[9]

The first somatic treatment that produced a permanent genetic change was performed in 1993.[citation needed]

Gene therapy is a way to fix a genetic problem at its source. The polymers are either translated into proteins, interfere with target gene expression, or possibly correct genetic mutations.

The most common form uses DNA that encodes a functional, therapeutic gene to replace a mutated gene. The polymer molecule is packaged within a “vector”, which carries the molecule inside cells.

Early clinical failures led to dismissals of gene therapy. Clinical successes since 2006 regained researchers’ attention, although as of 2014[update], it was still largely an experimental technique.[10] These include treatment of retinal diseases Leber’s congenital amaurosis[11][12][13][14] and choroideremia,[15] X-linked SCID,[16] ADA-SCID,[17][18] adrenoleukodystrophy,[19] chronic lymphocytic leukemia (CLL),[20] acute lymphocytic leukemia (ALL),[21] multiple myeloma,[22] haemophilia,[18] and Parkinson’s disease.[23] Between 2013 and April 2014, US companies invested over $600 million in the field.[24]

The first commercial gene therapy, Gendicine, was approved in China in 2003 for the treatment of certain cancers.[25] In 2011 Neovasculgen was registered in Russia as the first-in-class gene-therapy drug for treatment of peripheral artery disease, including critical limb ischemia.[26]In 2012 Glybera, a treatment for a rare inherited disorder, [1] became the first treatment to be approved for clinical use in either Europe or the United States after its endorsement by the European Commission.[10][27]

Following early advances in genetic engineering of bacteria, cells, and small animals, scientists started considering how to apply it to medicine. Two main approaches were considered replacing or disrupting defective genes.[28] Scientists focused on diseases caused by single-gene defects, such as cystic fibrosis, haemophilia, muscular dystrophy, thalassemia, and sickle cell anemia. Glybera treats one such disease, caused by a defect in lipoprotein lipase.[27]

DNA must be administered, reach the damaged cells, enter the cell and either express or disrupt a protein.[29] Multiple delivery techniques have been explored. The initial approach incorporated DNA into an engineered virus to deliver the DNA into a chromosome.[30][31] Naked DNA approaches have also been explored, especially in the context of vaccine development.[32]

Generally, efforts focused on administering a gene that causes a needed protein to be expressed. More recently, increased understanding of nuclease function has led to more direct DNA editing, using techniques such as zinc finger nucleases and CRISPR. The vector incorporates genes into chromosomes. The expressed nucleases then knock out and replace genes in the chromosome. As of 2014[update] these approaches involve removing cells from patients, editing a chromosome and returning the transformed cells to patients.[33]

Gene editing is a potential approach to alter the human genome to treat genetic diseases,[34] viral diseases,[35] and cancer.[36] As of 2016[update] these approaches were still years from being medicine.[37][38]

Gene therapy may be classified into two types:

In somatic cell gene therapy (SCGT), the therapeutic genes are transferred into any cell other than a gamete, germ cell, gametocyte, or undifferentiated stem cell. Any such modifications affect the individual patient only, and are not inherited by offspring. Somatic gene therapy represents mainstream basic and clinical research, in which therapeutic DNA (either integrated in the genome or as an external episome or plasmid) is used to treat disease.

Over 600 clinical trials utilizing SCGT are underway[when?] in the US. Most focus on severe genetic disorders, including immunodeficiencies, haemophilia, thalassaemia, and cystic fibrosis. Such single gene disorders are good candidates for somatic cell therapy. The complete correction of a genetic disorder or the replacement of multiple genes is not yet possible. Only a few of the trials are in the advanced stages.[39] [needs update]

In germline gene therapy (GGT), germ cells (sperm or egg cells) are modified by the introduction of functional genes into their genomes. Modifying a germ cell causes all the organism’s cells to contain the modified gene. The change is therefore heritable and passed on to later generations. Australia, Canada, Germany, Israel, Switzerland, and the Netherlands[40] prohibit GGT for application in human beings, for technical and ethical reasons, including insufficient knowledge about possible risks to future generations[40] and higher risks versus SCGT.[41] The US has no federal controls specifically addressing human genetic modification (beyond FDA regulations for therapies in general).[40][42][43][44]

The delivery of DNA into cells can be accomplished by multiple methods. The two major classes are recombinant viruses (sometimes called biological nanoparticles or viral vectors) and naked DNA or DNA complexes (non-viral methods).

In order to replicate, viruses introduce their genetic material into the host cell, tricking the host’s cellular machinery into using it as blueprints for viral proteins. Retroviruses go a stage further by having their genetic material copied into the genome of the host cell. Scientists exploit this by substituting a virus’s genetic material with therapeutic DNA. (The term ‘DNA’ may be an oversimplification, as some viruses contain RNA, and gene therapy could take this form as well.) A number of viruses have been used for human gene therapy, including retroviruses, adenoviruses, herpes simplex, vaccinia, and adeno-associated virus.[4] Like the genetic material (DNA or RNA) in viruses, therapeutic DNA can be designed to simply serve as a temporary blueprint that is degraded naturally or (at least theoretically) to enter the host’s genome, becoming a permanent part of the host’s DNA in infected cells.

Non-viral methods present certain advantages over viral methods, such as large scale production and low host immunogenicity. However, non-viral methods initially produced lower levels of transfection and gene expression, and thus lower therapeutic efficacy. Later technology remedied this deficiency.[citation needed]

Methods for non-viral gene therapy include the injection of naked DNA, electroporation, the gene gun, sonoporation, magnetofection, the use of oligonucleotides, lipoplexes, dendrimers, and inorganic nanoparticles.

Some of the unsolved problems include:

Three patients’ deaths have been reported in gene therapy trials, putting the field under close scrutiny. The first was that of Jesse Gelsinger, who died in 1999 because of immune rejection response.[51] One X-SCID patient died of leukemia in 2003.[9] In 2007, a rheumatoid arthritis patient died from an infection; the subsequent investigation concluded that the death was not related to gene therapy.[52]

In 1972 Friedmann and Roblin authored a paper in Science titled “Gene therapy for human genetic disease?”[53] Rogers (1970) was cited for proposing that exogenous good DNA be used to replace the defective DNA in those who suffer from genetic defects.[54]

In 1984 a retrovirus vector system was designed that could efficiently insert foreign genes into mammalian chromosomes.[55]

The first approved gene therapy clinical research in the US took place on 14 September 1990, at the National Institutes of Health (NIH), under the direction of William French Anderson.[56] Four-year-old Ashanti DeSilva received treatment for a genetic defect that left her with ADA-SCID, a severe immune system deficiency. The defective gene of the patient’s blood cells was replaced by the functional variant. Ashantis immune system was partially restored by the therapy. Production of the missing enzyme was temporarily stimulated, but the new cells with functional genes were not generated. She led a normal life only with the regular injections performed every two months. The effects were successful, but temporary.[57]

Cancer gene therapy was introduced in 1992/93 (Trojan et al. 1993).[58] The treatment of glioblastoma multiforme, the malignant brain tumor whose outcome is always fatal, was done using a vector expressing antisense IGF-I RNA (clinical trial approved by NIH protocolno.1602 November 24, 1993,[59] and by the FDA in 1994). This therapy also represents the beginning of cancer immunogene therapy, a treatment which proves to be effective due to the anti-tumor mechanism of IGF-I antisense, which is related to strong immune and apoptotic phenomena.

In 1992 Claudio Bordignon, working at the Vita-Salute San Raffaele University, performed the first gene therapy procedure using hematopoietic stem cells as vectors to deliver genes intended to correct hereditary diseases.[60] In 2002 this work led to the publication of the first successful gene therapy treatment for adenosine deaminase deficiency (ADA-SCID). The success of a multi-center trial for treating children with SCID (severe combined immune deficiency or “bubble boy” disease) from 2000 and 2002, was questioned when two of the ten children treated at the trial’s Paris center developed a leukemia-like condition. Clinical trials were halted temporarily in 2002, but resumed after regulatory review of the protocol in the US, the United Kingdom, France, Italy, and Germany.[61]

In 1993 Andrew Gobea was born with SCID following prenatal genetic screening. Blood was removed from his mother’s placenta and umbilical cord immediately after birth, to acquire stem cells. The allele that codes for adenosine deaminase (ADA) was obtained and inserted into a retrovirus. Retroviruses and stem cells were mixed, after which the viruses inserted the gene into the stem cell chromosomes. Stem cells containing the working ADA gene were injected into Andrew’s blood. Injections of the ADA enzyme were also given weekly. For four years T cells (white blood cells), produced by stem cells, made ADA enzymes using the ADA gene. After four years more treatment was needed.[62]

Jesse Gelsinger’s death in 1999 impeded gene therapy research in the US.[63][64] As a result, the FDA suspended several clinical trials pending the reevaluation of ethical and procedural practices.[65]

The modified cancer gene therapy strategy of antisense IGF-I RNA (NIH n 1602)[59] using antisense / triple helix anti-IGF-I approach was registered in 2002 by Wiley gene therapy clinical trial – n 635 and 636. The approach has shown promising results in the treatment of six different malignant tumors: glioblastoma, cancers of liver, colon, prostate, uterus, and ovary (Collaborative NATO Science Programme on Gene Therapy USA, France, Poland n LST 980517 conducted by J. Trojan) (Trojan et al., 2012). This anti-gene antisense/triple helix therapy has proven to be efficient, due to the mechanism stopping simultaneously IGF-I expression on translation and transcription levels, strengthening anti-tumor immune and apoptotic phenomena.

Sickle-cell disease can be treated in mice.[66] The mice which have essentially the same defect that causes human cases used a viral vector to induce production of fetal hemoglobin (HbF), which normally ceases to be produced shortly after birth. In humans, the use of hydroxyurea to stimulate the production of HbF temporarily alleviates sickle cell symptoms. The researchers demonstrated this treatment to be a more permanent means to increase therapeutic HbF production.[67]

A new gene therapy approach repaired errors in messenger RNA derived from defective genes. This technique has the potential to treat thalassaemia, cystic fibrosis and some cancers.[68]

Researchers created liposomes 25 nanometers across that can carry therapeutic DNA through pores in the nuclear membrane.[69]

In 2003 a research team inserted genes into the brain for the first time. They used liposomes coated in a polymer called polyethylene glycol, which unlike viral vectors, are small enough to cross the bloodbrain barrier.[70]

Short pieces of double-stranded RNA (short, interfering RNAs or siRNAs) are used by cells to degrade RNA of a particular sequence. If a siRNA is designed to match the RNA copied from a faulty gene, then the abnormal protein product of that gene will not be produced.[71]

Gendicine is a cancer gene therapy that delivers the tumor suppressor gene p53 using an engineered adenovirus. In 2003, it was approved in China for the treatment of head and neck squamous cell carcinoma.[25]

In March researchers announced the successful use of gene therapy to treat two adult patients for X-linked chronic granulomatous disease, a disease which affects myeloid cells and damages the immune system. The study is the first to show that gene therapy can treat the myeloid system.[72]

In May a team reported a way to prevent the immune system from rejecting a newly delivered gene.[73] Similar to organ transplantation, gene therapy has been plagued by this problem. The immune system normally recognizes the new gene as foreign and rejects the cells carrying it. The research utilized a newly uncovered network of genes regulated by molecules known as microRNAs. This natural function selectively obscured their therapeutic gene in immune system cells and protected it from discovery. Mice infected with the gene containing an immune-cell microRNA target sequence did not reject the gene.

In August scientists successfully treated metastatic melanoma in two patients using killer T cells genetically retargeted to attack the cancer cells.[74]

In November researchers reported on the use of VRX496, a gene-based immunotherapy for the treatment of HIV that uses a lentiviral vector to deliver an antisense gene against the HIV envelope. In a phase I clinical trial, five subjects with chronic HIV infection who had failed to respond to at least two antiretroviral regimens were treated. A single intravenous infusion of autologous CD4 T cells genetically modified with VRX496 was well tolerated. All patients had stable or decreased viral load; four of the five patients had stable or increased CD4 T cell counts. All five patients had stable or increased immune response to HIV antigens and other pathogens. This was the first evaluation of a lentiviral vector administered in a US human clinical trial.[75][76]

In May researchers announced the first gene therapy trial for inherited retinal disease. The first operation was carried out on a 23-year-old British male, Robert Johnson, in early 2007.[77]

Leber’s congenital amaurosis is an inherited blinding disease caused by mutations in the RPE65 gene. The results of a small clinical trial in children were published in April.[11] Delivery of recombinant adeno-associated virus (AAV) carrying RPE65 yielded positive results. In May two more groups reported positive results in independent clinical trials using gene therapy to treat the condition. In all three clinical trials, patients recovered functional vision without apparent side-effects.[11][12][13][14]

In September researchers were able to give trichromatic vision to squirrel monkeys.[78] In November 2009, researchers halted a fatal genetic disorder called adrenoleukodystrophy in two children using a lentivirus vector to deliver a functioning version of ABCD1, the gene that is mutated in the disorder.[79]

An April paper reported that gene therapy addressed achromatopsia (color blindness) in dogs by targeting cone photoreceptors. Cone function and day vision were restored for at least 33 months in two young specimens. The therapy was less efficient for older dogs.[80]

In September it was announced that an 18-year-old male patient in France with beta-thalassemia major had been successfully treated.[81] Beta-thalassemia major is an inherited blood disease in which beta haemoglobin is missing and patients are dependent on regular lifelong blood transfusions.[82] The technique used a lentiviral vector to transduce the human -globin gene into purified blood and marrow cells obtained from the patient in June 2007.[83] The patient’s haemoglobin levels were stable at 9 to 10 g/dL. About a third of the hemoglobin contained the form introduced by the viral vector and blood transfusions were not needed.[83][84] Further clinical trials were planned.[85] Bone marrow transplants are the only cure for thalassemia, but 75% of patients do not find a matching donor.[84]

Cancer immunogene therapy using modified antigene, antisense/triple helix approach was introduced in South America in 2010/11 in La Sabana University, Bogota (Ethical Committee 14 December 2010, no P-004-10). Considering the ethical aspect of gene diagnostic and gene therapy targeting IGF-I, the IGF-I expressing tumors i.e. lung and epidermis cancers were treated (Trojan et al. 2016).[86][87]

In 2007 and 2008, a man (Timothy Ray Brown) was cured of HIV by repeated hematopoietic stem cell transplantation (see also allogeneic stem cell transplantation, allogeneic bone marrow transplantation, allotransplantation) with double-delta-32 mutation which disables the CCR5 receptor. This cure was accepted by the medical community in 2011.[88] It required complete ablation of existing bone marrow, which is very debilitating.

In August two of three subjects of a pilot study were confirmed to have been cured from chronic lymphocytic leukemia (CLL). The therapy used genetically modified T cells to attack cells that expressed the CD19 protein to fight the disease.[20] In 2013, the researchers announced that 26 of 59 patients had achieved complete remission and the original patient had remained tumor-free.[89]

Human HGF plasmid DNA therapy of cardiomyocytes is being examined as a potential treatment for coronary artery disease as well as treatment for the damage that occurs to the heart after myocardial infarction.[90][91]

In 2011 Neovasculgen was registered in Russia as the first-in-class gene-therapy drug for treatment of peripheral artery disease, including critical limb ischemia; it delivers the gene encoding for VEGF.[92][26] Neovasculogen is a plasmid encoding the CMV promoter and the 165 amino acid form of VEGF.[93][94]

The FDA approved Phase 1 clinical trials on thalassemia major patients in the US for 10 participants in July.[95] The study was expected to continue until 2015.[85]

In July 2012, the European Medicines Agency recommended approval of a gene therapy treatment for the first time in either Europe or the United States. The treatment used Alipogene tiparvovec (Glybera) to compensate for lipoprotein lipase deficiency, which can cause severe pancreatitis.[96] The recommendation was endorsed by the European Commission in November 2012[10][27][97][98] and commercial rollout began in late 2014.[99] Alipogene tiparvovec was expected to cost around $1.6 million per treatment in 2012,[100] revised to $1 million in 2015,[101] making it the most expensive medicine in the world at the time.[102] As of 2016[update], only the patients treated in clinical trials and a patient who paid the full price for treatment have received the drug.[103]

In December 2012, it was reported that 10 of 13 patients with multiple myeloma were in remission “or very close to it” three months after being injected with a treatment involving genetically engineered T cells to target proteins NY-ESO-1 and LAGE-1, which exist only on cancerous myeloma cells.[22]

In March researchers reported that three of five adult subjects who had acute lymphocytic leukemia (ALL) had been in remission for five months to two years after being treated with genetically modified T cells which attacked cells with CD19 genes on their surface, i.e. all B-cells, cancerous or not. The researchers believed that the patients’ immune systems would make normal T-cells and B-cells after a couple of months. They were also given bone marrow. One patient relapsed and died and one died of a blood clot unrelated to the disease.[21]

Following encouraging Phase 1 trials, in April, researchers announced they were starting Phase 2 clinical trials (called CUPID2 and SERCA-LVAD) on 250 patients[104] at several hospitals to combat heart disease. The therapy was designed to increase the levels of SERCA2, a protein in heart muscles, improving muscle function.[105] The FDA granted this a Breakthrough Therapy Designation to accelerate the trial and approval process.[106] In 2016 it was reported that no improvement was found from the CUPID 2 trial.[107]

In July researchers reported promising results for six children with two severe hereditary diseases had been treated with a partially deactivated lentivirus to replace a faulty gene and after 732 months. Three of the children had metachromatic leukodystrophy, which causes children to lose cognitive and motor skills.[108] The other children had Wiskott-Aldrich syndrome, which leaves them to open to infection, autoimmune diseases, and cancer.[109] Follow up trials with gene therapy on another six children with Wiskott-Aldrich syndrome were also reported as promising.[110][111]

In October researchers reported that two children born with adenosine deaminase severe combined immunodeficiency disease (ADA-SCID) had been treated with genetically engineered stem cells 18 months previously and that their immune systems were showing signs of full recovery. Another three children were making progress.[18] In 2014 a further 18 children with ADA-SCID were cured by gene therapy.[112] ADA-SCID children have no functioning immune system and are sometimes known as “bubble children.”[18]

Also in October researchers reported that they had treated six hemophilia sufferers in early 2011 using an adeno-associated virus. Over two years later all six were producing clotting factor.[18][113]

In January researchers reported that six choroideremia patients had been treated with adeno-associated virus with a copy of REP1. Over a six-month to two-year period all had improved their sight.[114][115] By 2016, 32 patients had been treated with positive results and researchers were hopeful the treatment would be long-lasting.[15] Choroideremia is an inherited genetic eye disease with no approved treatment, leading to loss of sight.

In March researchers reported that 12 HIV patients had been treated since 2009 in a trial with a genetically engineered virus with a rare mutation (CCR5 deficiency) known to protect against HIV with promising results.[116][117]

Clinical trials of gene therapy for sickle cell disease were started in 2014.[118][119] There is a need for high quality randomised controlled trials assessing the risks and benefits involved with gene therapy for people with sickle cell disease.[120][needs update]

In February LentiGlobin BB305, a gene therapy treatment undergoing clinical trials for treatment of beta thalassemia gained FDA “breakthrough” status after several patients were able to forgo the frequent blood transfusions usually required to treat the disease.[121]

In March researchers delivered a recombinant gene encoding a broadly neutralizing antibody into monkeys infected with simian HIV; the monkeys’ cells produced the antibody, which cleared them of HIV. The technique is named immunoprophylaxis by gene transfer (IGT). Animal tests for antibodies to ebola, malaria, influenza, and hepatitis were underway.[122][123]

In March, scientists, including an inventor of CRISPR, Jennifer Doudna, urged a worldwide moratorium on germline gene therapy, writing “scientists should avoid even attempting, in lax jurisdictions, germline genome modification for clinical application in humans” until the full implications “are discussed among scientific and governmental organizations”.[124][125][126][127]

In October, researchers announced that they had treated a baby girl, Layla Richards, with an experimental treatment using donor T-cells genetically engineered using TALEN to attack cancer cells. One year after the treatment she was still free of her cancer (a highly aggressive form of acute lymphoblastic leukaemia [ALL]).[128] Children with highly aggressive ALL normally have a very poor prognosis and Layla’s disease had been regarded as terminal before the treatment.[129]

In December, scientists of major world academies called for a moratorium on inheritable human genome edits, including those related to CRISPR-Cas9 technologies[130] but that basic research including embryo gene editing should continue.[131]

In April the Committee for Medicinal Products for Human Use of the European Medicines Agency endorsed a gene therapy treatment called Strimvelis[132][133] and the European Commission approved it in June.[134] This treats children born with adenosine deaminase deficiency and who have no functioning immune system. This was the second gene therapy treatment to be approved in Europe.[135]

In October, Chinese scientists reported they had started a trial to genetically modify T-cells from 10 adult patients with lung cancer and reinject the modified T-cells back into their bodies to attack the cancer cells. The T-cells had the PD-1 protein (which stops or slows the immune response) removed using CRISPR-Cas9.[136][137]

A 2016 Cochrane systematic review looking at data from four trials on topical cystic fibrosis transmembrane conductance regulator (CFTR) gene therapy does not support its clinical use as a mist inhaled into the lungs to treat cystic fibrosis patients with lung infections. One of the four trials did find weak evidence that liposome-based CFTR gene transfer therapy may lead to a small respiratory improvement for people with CF. This weak evidence is not enough to make a clinical recommendation for routine CFTR gene therapy.[138]

In February Kite Pharma announced results from a clinical trial of CAR-T cells in around a hundred people with advanced Non-Hodgkin lymphoma.[139]

In March, French scientists reported on clinical research of gene therapy to treat sickle-cell disease.[140]

In August, the FDA approved tisagenlecleucel for acute lymphoblastic leukemia.[141] Tisagenlecleucel is an adoptive cell transfer therapy for B-cell acute lymphoblastic leukemia; T cells from a person with cancer are removed, genetically engineered to make a specific T-cell receptor (a chimeric T cell receptor, or “CAR-T”) that reacts to the cancer, and are administered back to the person. The T cells are engineered to target a protein called CD19 that is common on B cells. This is the first form of gene therapy to be approved in the United States. In October, a similar therapy called axicabtagene ciloleucel was approved for non-Hodgkin lymphoma.[142]

In December the results of using an adeno-associated virus with blood clotting factor VIII to treat nine haemophilia A patients were published. Six of the seven patients on the high dose regime increased the level of the blood clotting VIII to normal levels. The low and medium dose regimes had no effect on the patient’s blood clotting levels.[143][144]

In December, the FDA approved Luxturna, the first in vivo gene therapy, for the treatment of blindness due to Leber’s congenital amaurosis.[145] The price of this treatment was 850,000 US dollars for both eyes.[146][147]

Speculated uses for gene therapy include:

Athletes might adopt gene therapy technologies to improve their performance.[148] Gene doping is not known to occur, but multiple gene therapies may have such effects. Kayser et al. argue that gene doping could level the playing field if all athletes receive equal access. Critics claim that any therapeutic intervention for non-therapeutic/enhancement purposes compromises the ethical foundations of medicine and sports.[149]

Genetic engineering could be used to cure diseases, but also to change physical appearance, metabolism, and even improve physical capabilities and mental faculties such as memory and intelligence. Ethical claims about germline engineering include beliefs that every fetus has a right to remain genetically unmodified, that parents hold the right to genetically modify their offspring, and that every child has the right to be born free of preventable diseases.[150][151][152] For parents, genetic engineering could be seen as another child enhancement technique to add to diet, exercise, education, training, cosmetics, and plastic surgery.[153][154] Another theorist claims that moral concerns limit but do not prohibit germline engineering.[155]

Possible regulatory schemes include a complete ban, provision to everyone, or professional self-regulation. The American Medical Associations Council on Ethical and Judicial Affairs stated that “genetic interventions to enhance traits should be considered permissible only in severely restricted situations: (1) clear and meaningful benefits to the fetus or child; (2) no trade-off with other characteristics or traits; and (3) equal access to the genetic technology, irrespective of income or other socioeconomic characteristics.”[156]

As early in the history of biotechnology as 1990, there have been scientists opposed to attempts to modify the human germline using these new tools,[157] and such concerns have continued as technology progressed.[158][159] With the advent of new techniques like CRISPR, in March 2015 a group of scientists urged a worldwide moratorium on clinical use of gene editing technologies to edit the human genome in a way that can be inherited.[124][125][126][127] In April 2015, researchers sparked controversy when they reported results of basic research to edit the DNA of non-viable human embryos using CRISPR.[160][161] A committee of the American National Academy of Sciences and National Academy of Medicine gave qualified support to human genome editing in 2017[162][163] once answers have been found to safety and efficiency problems “but only for serious conditions under stringent oversight.”[164]

Regulations covering genetic modification are part of general guidelines about human-involved biomedical research. There are no international treaties which are legally binding in this area, but there are recommendations for national laws from various bodies.

The Helsinki Declaration (Ethical Principles for Medical Research Involving Human Subjects) was amended by the World Medical Association’s General Assembly in 2008. This document provides principles physicians and researchers must consider when involving humans as research subjects. The Statement on Gene Therapy Research initiated by the Human Genome Organization (HUGO) in 2001 provides a legal baseline for all countries. HUGOs document emphasizes human freedom and adherence to human rights, and offers recommendations for somatic gene therapy, including the importance of recognizing public concerns about such research.[165]

No federal legislation lays out protocols or restrictions about human genetic engineering. This subject is governed by overlapping regulations from local and federal agencies, including the Department of Health and Human Services, the FDA and NIH’s Recombinant DNA Advisory Committee. Researchers seeking federal funds for an investigational new drug application, (commonly the case for somatic human genetic engineering,) must obey international and federal guidelines for the protection of human subjects.[166]

NIH serves as the main gene therapy regulator for federally funded research. Privately funded research is advised to follow these regulations. NIH provides funding for research that develops or enhances genetic engineering techniques and to evaluate the ethics and quality in current research. The NIH maintains a mandatory registry of human genetic engineering research protocols that includes all federally funded projects.

An NIH advisory committee published a set of guidelines on gene manipulation.[167] The guidelines discuss lab safety as well as human test subjects and various experimental types that involve genetic changes. Several sections specifically pertain to human genetic engineering, including Section III-C-1. This section describes required review processes and other aspects when seeking approval to begin clinical research involving genetic transfer into a human patient.[168] The protocol for a gene therapy clinical trial must be approved by the NIH’s Recombinant DNA Advisory Committee prior to any clinical trial beginning; this is different from any other kind of clinical trial.[167]

As with other kinds of drugs, the FDA regulates the quality and safety of gene therapy products and supervises how these products are used clinically. Therapeutic alteration of the human genome falls under the same regulatory requirements as any other medical treatment. Research involving human subjects, such as clinical trials, must be reviewed and approved by the FDA and an Institutional Review Board.[169][170]

Gene therapy is the basis for the plotline of the film I Am Legend[171] and the TV show Will Gene Therapy Change the Human Race?.[172] In 1994, gene therapy was a plot element in “The Erlenmeyer Flask”, the first season finale of The X-Files; it is also used in Stargate as a means of allowing humans to use Ancient technology.[173][174]

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Gene therapy – Wikipedia

Genetic engineering – Wikipedia

Genetic engineering, also called genetic modification or genetic manipulation, is the direct manipulation of an organism’s genes using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. As well as inserting genes, the process can be used to remove, or “knock out”, genes. The new DNA can be inserted randomly, or targeted to a specific part of the genome.

An organism that is generated through genetic engineering is considered to be genetically modified (GM) and the resulting entity is a genetically modified organism (GMO). The first GMO was a bacterium generated by Herbert Boyer and Stanley Cohen in 1973. Rudolf Jaenisch created the first GM animal when he inserted foreign DNA into a mouse in 1974. The first company to focus on genetic engineering, Genentech, was founded in 1976 and started the production of human proteins. Genetically engineered human insulin was produced in 1978 and insulin-producing bacteria were commercialised in 1982. Genetically modified food has been sold since 1994, with the release of the Flavr Savr tomato. The Flavr Savr was engineered to have a longer shelf life, but most current GM crops are modified to increase resistance to insects and herbicides. GloFish, the first GMO designed as a pet, was sold in the United States in December 2003. In 2016 salmon modified with a growth hormone were sold.

Genetic engineering has been applied in numerous fields including research, medicine, industrial biotechnology and agriculture. In research GMOs are used to study gene function and expression through loss of function, gain of function, tracking and expression experiments. By knocking out genes responsible for certain conditions it is possible to create animal model organisms of human diseases. As well as producing hormones, vaccines and other drugs genetic engineering has the potential to cure genetic diseases through gene therapy. The same techniques that are used to produce drugs can also have industrial applications such as producing enzymes for laundry detergent, cheeses and other products.

The rise of commercialised genetically modified crops has provided economic benefit to farmers in many different countries, but has also been the source of most of the controversy surrounding the technology. This has been present since its early use; the first field trials were destroyed by anti-GM activists. Although there is a scientific consensus that currently available food derived from GM crops poses no greater risk to human health than conventional food, GM food safety is a leading concern with critics. Gene flow, impact on non-target organisms, control of the food supply and intellectual property rights have also been raised as potential issues. These concerns have led to the development of a regulatory framework, which started in 1975. It has led to an international treaty, the Cartagena Protocol on Biosafety, that was adopted in 2000. Individual countries have developed their own regulatory systems regarding GMOs, with the most marked differences occurring between the US and Europe.

Genetic engineering is a process that alters the genetic structure of an organism by either removing or introducing DNA. Unlike traditional animal and plant breeding, which involves doing multiple crosses and then selecting for the organism with the desired phenotype, genetic engineering takes the gene directly from one organism and inserts it in the other. This is much faster, can be used to insert any genes from any organism (even ones from different domains) and prevents other undesirable genes from also being added.[3]

Genetic engineering could potentially fix severe genetic disorders in humans by replacing the defective gene with a functioning one.[4] It is an important tool in research that allows the function of specific genes to be studied.[5] Drugs, vaccines and other products have been harvested from organisms engineered to produce them.[6] Crops have been developed that aid food security by increasing yield, nutritional value and tolerance to environmental stresses.[7]

The DNA can be introduced directly into the host organism or into a cell that is then fused or hybridised with the host.[8] This relies on recombinant nucleic acid techniques to form new combinations of heritable genetic material followed by the incorporation of that material either indirectly through a vector system or directly through micro-injection, macro-injection or micro-encapsulation.[9]

Genetic engineering does not normally include traditional breeding, in vitro fertilisation, induction of polyploidy, mutagenesis and cell fusion techniques that do not use recombinant nucleic acids or a genetically modified organism in the process.[8] However, some broad definitions of genetic engineering include selective breeding.[9] Cloning and stem cell research, although not considered genetic engineering,[10] are closely related and genetic engineering can be used within them.[11] Synthetic biology is an emerging discipline that takes genetic engineering a step further by introducing artificially synthesised material into an organism.[12]

Plants, animals or micro organisms that have been changed through genetic engineering are termed genetically modified organisms or GMOs.[13] If genetic material from another species is added to the host, the resulting organism is called transgenic. If genetic material from the same species or a species that can naturally breed with the host is used the resulting organism is called cisgenic.[14] If genetic engineering is used to remove genetic material from the target organism the resulting organism is termed a knockout organism.[15] In Europe genetic modification is synonymous with genetic engineering while within the United States of America and Canada genetic modification can also be used to refer to more conventional breeding methods.[16][17][18]

Humans have altered the genomes of species for thousands of years through selective breeding, or artificial selection[19]:1[20]:1 as contrasted with natural selection. More recently, mutation breeding has used exposure to chemicals or radiation to produce a high frequency of random mutations, for selective breeding purposes. Genetic engineering as the direct manipulation of DNA by humans outside breeding and mutations has only existed since the 1970s. The term “genetic engineering” was first coined by Jack Williamson in his science fiction novel Dragon’s Island, published in 1951[21] one year before DNA’s role in heredity was confirmed by Alfred Hershey and Martha Chase,[22] and two years before James Watson and Francis Crick showed that the DNA molecule has a double-helix structure though the general concept of direct genetic manipulation was explored in rudimentary form in Stanley G. Weinbaum’s 1936 science fiction story Proteus Island.[23][24]

In 1972, Paul Berg created the first recombinant DNA molecules by combining DNA from the monkey virus SV40 with that of the lambda virus.[25] In 1973 Herbert Boyer and Stanley Cohen created the first transgenic organism by inserting antibiotic resistance genes into the plasmid of an Escherichia coli bacterium.[26][27] A year later Rudolf Jaenisch created a transgenic mouse by introducing foreign DNA into its embryo, making it the worlds first transgenic animal[28] These achievements led to concerns in the scientific community about potential risks from genetic engineering, which were first discussed in depth at the Asilomar Conference in 1975. One of the main recommendations from this meeting was that government oversight of recombinant DNA research should be established until the technology was deemed safe.[29][30]

In 1976 Genentech, the first genetic engineering company, was founded by Herbert Boyer and Robert Swanson and a year later the company produced a human protein (somatostatin) in E.coli. Genentech announced the production of genetically engineered human insulin in 1978.[31] In 1980, the U.S. Supreme Court in the Diamond v. Chakrabarty case ruled that genetically altered life could be patented.[32] The insulin produced by bacteria was approved for release by the Food and Drug Administration (FDA) in 1982.[33]

In 1983, a biotech company, Advanced Genetic Sciences (AGS) applied for U.S. government authorisation to perform field tests with the ice-minus strain of Pseudomonas syringae to protect crops from frost, but environmental groups and protestors delayed the field tests for four years with legal challenges.[34] In 1987, the ice-minus strain of P. syringae became the first genetically modified organism (GMO) to be released into the environment[35] when a strawberry field and a potato field in California were sprayed with it.[36] Both test fields were attacked by activist groups the night before the tests occurred: “The world’s first trial site attracted the world’s first field trasher”.[35]

The first field trials of genetically engineered plants occurred in France and the US in 1986, tobacco plants were engineered to be resistant to herbicides.[37] The Peoples Republic of China was the first country to commercialise transgenic plants, introducing a virus-resistant tobacco in 1992.[38] In 1994 Calgene attained approval to commercially release the first genetically modified food, the Flavr Savr, a tomato engineered to have a longer shelf life.[39] In 1994, the European Union approved tobacco engineered to be resistant to the herbicide bromoxynil, making it the first genetically engineered crop commercialised in Europe.[40] In 1995, Bt Potato was approved safe by the Environmental Protection Agency, after having been approved by the FDA, making it the first pesticide producing crop to be approved in the US.[41] In 2009 11 transgenic crops were grown commercially in 25 countries, the largest of which by area grown were the US, Brazil, Argentina, India, Canada, China, Paraguay and South Africa.[42]

In 2010, scientists at the J. Craig Venter Institute created the first synthetic genome and inserted it into an empty bacterial cell. The resulting bacterium, named Mycoplasma laboratorium, could replicate and produce proteins.[43][44] Four years later this was taken a step further when a bacterium was developed that replicated a plasmid containing a unique base pair, creating the first organism engineered to use an expanded genetic alphabet.[45][46] In 2012, Jennifer Doudna and Emmanuelle Charpentier collaborated to develop the CRISPR/Cas9 system,[47][48] a technique which can be used to easily and specifically alter the genome of almost any organism.[49]

Creating a GMO is a multi-step process. Genetic engineers must first choose what gene they wish to insert into the organism. This is driven by what the aim is for the resultant organism and is built on earlier research. Genetic screens can be carried out to determine potential genes and further tests then used to identify the best candidates. The development of microarrays, transcriptomics and genome sequencing has made it much easier to find suitable genes.[50] Luck also plays its part; the round-up ready gene was discovered after scientists noticed a bacterium thriving in the presence of the herbicide.[51]

The next step is to isolate the candidate gene. The cell containing the gene is opened and the DNA is purified.[52] The gene is separated by using restriction enzymes to cut the DNA into fragments[53] or polymerase chain reaction (PCR) to amplify up the gene segment.[54] These segments can then be extracted through gel electrophoresis. If the chosen gene or the donor organism’s genome has been well studied it may already be accessible from a genetic library. If the DNA sequence is known, but no copies of the gene are available, it can also be artificially synthesised.[55] Once isolated the gene is ligated into a plasmid that is then inserted into a bacterium. The plasmid is replicated when the bacteria divide, ensuring unlimited copies of the gene are available.[56]

Before the gene is inserted into the target organism it must be combined with other genetic elements. These include a promoter and terminator region, which initiate and end transcription. A selectable marker gene is added, which in most cases confers antibiotic resistance, so researchers can easily determine which cells have been successfully transformed. The gene can also be modified at this stage for better expression or effectiveness. These manipulations are carried out using recombinant DNA techniques, such as restriction digests, ligations and molecular cloning.[57]

There are a number of techniques available for inserting the gene into the host genome. Some bacteria can naturally take up foreign DNA. This ability can be induced in other bacteria via stress (e.g. thermal or electric shock), which increases the cell membrane’s permeability to DNA; up-taken DNA can either integrate with the genome or exist as extrachromosomal DNA. DNA is generally inserted into animal cells using microinjection, where it can be injected through the cell’s nuclear envelope directly into the nucleus, or through the use of viral vectors.[58]

In plants the DNA is often inserted using Agrobacterium-mediated recombination,[59] taking advantage of the Agrobacteriums T-DNA sequence that allows natural insertion of genetic material into plant cells.[60] Other methods include biolistics, where particles of gold or tungsten are coated with DNA and then shot into young plant cells,[61] and electroporation, which involves using an electric shock to make the cell membrane permeable to plasmid DNA. Due to the damage caused to the cells and DNA the transformation efficiency of biolistics and electroporation is lower than agrobacterial transformation and microinjection.[62]

As only a single cell is transformed with genetic material, the organism must be regenerated from that single cell. In plants this is accomplished through the use of tissue c ulture.[63][64] In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells.[65] Bacteria consist of a single cell and reproduce clonally so regeneration is not necessary. Selectable markers are used to easily differentiate transformed from untransformed cells. These markers are usually present in the transgenic organism, although a number of strategies have been developed that can remove the selectable marker from the mature transgenic plant.[66]

Further testing using PCR, Southern hybridization, and DNA sequencing is conducted to confirm that an organism contains the new gene.[67] These tests can also confirm the chromosomal location and copy number of the inserted gene. The presence of the gene does not guarantee it will be expressed at appropriate levels in the target tissue so methods that look for and measure the gene products (RNA and protein) are also used. These include northern hybridisation, quantitative RT-PCR, Western blot, immunofluorescence, ELISA and phenotypic analysis.[68]

The new genetic material can be inserted randomly within the host genome or targeted to a specific location. The technique of gene targeting uses homologous recombination to make desired changes to a specific endogenous gene. This tends to occur at a relatively low frequency in plants and animals and generally requires the use of selectable markers. The frequency of gene targeting can be greatly enhanced through genome editing. Genome editing uses artificially engineered nucleases that create specific double-stranded breaks at desired locations in the genome, and use the cells endogenous mechanisms to repair the induced break by the natural processes of homologous recombination and nonhomologous end-joining. There are four families of engineered nucleases: meganucleases,[69][70] zinc finger nucleases,[71][72] transcription activator-like effector nucleases (TALENs),[73][74] and the Cas9-guideRNA system (adapted from CRISPR).[75][76] TALEN and CRISPR are the two most commonly used and each has its own advantages.[77] TALENs have greater target specificity, while CRISPR is easier to design and more efficient.[77] In addition to enhancing gene targeting, engineered nucleases can be used to introduce mutations at endogenous genes that generate a gene knockout.[78][79]

Genetic engineering has applications in medicine, research, industry and agriculture and can be used on a wide range of plants, animals and micro organisms. Bacteria, the first organisms to be genetically modified, can have plasmid DNA inserted containing new genes that code for medicines or enzymes that process food and other substrates.[80][81] Plants have been modified for insect protection, herbicide resistance, virus resistance, enhanced nutrition, tolerance to environmental pressures and the production of edible vaccines.[82] Most commercialised GMOs are insect resistant or herbicide tolerant crop plants.[83] Genetically modified animals have been used for research, model animals and the production of agricultural or pharmaceutical products. The genetically modified animals include animals with genes knocked out, increased susceptibility to disease, hormones for extra growth and the ability to express proteins in their milk.[84]

Genetic engineering has many applications to medicine that include the manufacturing of drugs, creation of model animals that mimic human conditions and gene therapy. One of the earliest uses of genetic engineering was to mass-produce human insulin in bacteria.[31] This application has now been applied to, human growth hormones, follicle stimulating hormones (for treating infertility), human albumin, monoclonal antibodies, antihemophilic factors, vaccines and many other drugs.[85][86] Mouse hybridomas, cells fused together to create monoclonal antibodies, have been adapted through genetic engineering to create human monoclonal antibodies.[87] In 2017, genetic engineering of chimeric antigen receptors on a patient’s own T-cells was approved by the U.S. FDA as a treatment for the cancer acute lymphoblastic leukemia. Genetically engineered viruses are being developed that can still confer immunity, but lack the infectious sequences.[88]

Genetic engineering is also used to create animal models of human diseases. Genetically modified mice are the most common genetically engineered animal model.[89] They have been used to study and model cancer (the oncomouse), obesity, heart disease, diabetes, arthritis, substance abuse, anxiety, aging and Parkinson disease.[90] Potential cures can be tested against these mouse models. Also genetically modified pigs have been bred with the aim of increasing the success of pig to human organ transplantation.[91]

Gene therapy is the genetic engineering of humans, generally by replacing defective genes with effective ones. Clinical research using somatic gene therapy has been conducted with several diseases, including X-linked SCID,[92] chronic lymphocytic leukemia (CLL),[93][94] and Parkinson’s disease.[95] In 2012, Alipogene tiparvovec became the first gene therapy treatment to be approved for clinical use.[96][97] In 2015 a virus was used to insert a healthy gene into the skin cells of a boy suffering from a rare skin disease, epidermolysis bullosa, in order to grow, and then graft healthy skin onto 80 percent of the boy’s body which was affected by the illness.[98]

Germline gene therapy would result in any change being inheritable, which has raised concerns within the scientific community.[99][100] In 2015, CRISPR was used to edit the DNA of non-viable human embryos,[101][102] leading scientists of major world academies to call for a moratorium on inheritable human genome edits.[103] There are also concerns that the technology could be used not just for treatment, but for enhancement, modification or alteration of a human beings’ appearance, adaptability, intelligence, character or behavior.[104] The distinction between cure and enhancement can also be difficult to establish.[105] In November 2018, He Jiankui announced that he had edited the genomes of two human embryos, to attempt to disable the CCR5 gene, which codes for a receptor that HIV uses to enter cells. He said that twin girls, Lulu and Nana, had been born a few weeks earlier. He said that the girls still carried functional copies of CCR5 along with disabled CCR5 (mosaicism) and were still vulnerable to HIV. The work was widely condemned as unethical, dangerous, and premature.[106]

Researchers are altering the genome of pigs to induce the growth of human organs to be used in transplants. Scientists are creating “gene drives”, changing the genomes of mosquitoes to make them immune to malaria, and then looking to spread the genetically altered mosquitoes throughout the mosquito population in the hopes of eliminating the disease.[107]

Genetic engineering is an important tool for natural scientists, with the creation of transgenic organisms one of the most important tools for analysis of gene function.[108] Genes and other genetic information from a wide range of organisms can be inserted into bacteria for storage and modification, creating genetically modified bacteria in the process. Bacteria are cheap, easy to grow, clonal, multiply quickly, relatively easy to transform and can be stored at -80C almost indefinitely. Once a gene is isolated it can be stored inside the bacteria providing an unlimited supply for research.[109]Organisms are genetically engineered to discover the functions of certain genes. This could be the effect on the phenotype of the organism, where the gene is expressed or what other genes it interacts with. These experiments generally involve loss of function, gain of function, tracking and expression.

Organisms can have their cells transformed with a gene coding for a useful protein, such as an enzyme, so that they will overexpress the desired protein. Mass quantities of the protein can then be manufactured by growing the transformed organism in bioreactor equipment using industrial fermentation, and then purifying the protein.[113] Some genes do not work well in bacteria, so yeast, insect cells or mammalians cells can also be used.[114] These techniques are used to produce medicines such as insulin, human growth hormone, and vaccines, supplements such as tryptophan, aid in the production of food (chymosin in cheese making) and fuels.[115] Other applications with genetically engineered bacteria could involve making them perform tasks outside their natural cycle, such as making biofuels,[116] cleaning up oil spills, carbon and other toxic waste[117] and detecting arsenic in drinking water.[118] Certain genetically modified microbes can also be used in biomining and bioremediation, due to their ability to extract heavy metals from their environment and incorporate them into compounds that are more easily recoverable.[119]

In materials science, a genetically modified virus has been used in a research laboratory as a scaffold for assembling a more environmentally friendly lithium-ion battery.[120][121] Bacteria have also been engineered to function as sensors by expressing a fluorescent protein under certain environmental conditions.[122]

One of the best-known and controversial applications of genetic engineering is the creation and use of genetically modified crops or genetically modified livestock to produce genetically modified food. Crops have been developed to increase production, increase tolerance to abiotic stresses, alter the composition of the food, or to produce novel products.[124]

The first crops to be released commercially on a large scale provided protection from insect pests or tolerance to herbicides. Fungal and virus resistant crops have also been developed or are in development.[125][126] This make the insect and weed management of crops easier and can indirectly increase crop yield.[127][128] GM crops that directly improve yield by accelerating growth or making the plant more hardy (by improving salt, cold or drought tolerance) are also under development.[129] In 2016 Salmon have been genetically modified with growth hormones to reach normal adult size much faster.[130]

GMOs have been developed that modify the quality of produce by increasing the nutritional value or providing more industrially useful qualities or quantities.[129] The Amflora potato produces a more industrially useful blend of starches. Soybeans and canola have been genetically modified to produce more healthy oils.[131][132] The first commercialised GM food was a tomato that had delayed ripening, increasing its shelf life.[133]

Plants and animals have been engineered to produce materials they do not normally make. Pharming uses crops and animals as bioreactors to produce vaccines, drug intermediates, or the drugs themselves; the useful product is purified from the harvest and then used in the standard pharmaceutical production process.[134] Cows and goats have been engineered to express drugs and other proteins in their milk, and in 2009 the FDA approved a drug produced in goat milk.[135][136]

Genetic engineering has potential applications in conservation and natural area management. Gene transfer through viral vectors has been proposed as a means of controlling invasive species as well as vaccinating threatened fauna from disease.[137] Transgenic trees have been suggested as a way to confer resistance to pathogens in wild populations.[138] With the increasing risks of maladaptation in organisms as a result of climate change and other perturbations, facilitated adaptation through gene tweaking could be one solution to reducing extinction risks.[139] Applications of genetic engineering in conservation are thus far mostly theoretical and have yet to be put into practice.

Genetic engineering is also being used to create microbial art.[140] Some bacteria have been genetically engineered to create black and white photographs.[141] Novelty items such as lavender-colored carnations,[142] blue roses,[143] and glowing fish[144][145] have also been produced through genetic engineering.

The regulation of genetic engineering concerns the approaches taken by governments to assess and manage the risks associated with the development and release of GMOs. The development of a regulatory framework began in 1975, at Asilomar, California.[146] The Asilomar meeting recommended a set of voluntary guidelines regarding the use of recombinant technology.[147] As the technology improved the US established a committee at the Office of Science and Technology,[148] which assigned regulatory approval of GM food to the USDA, FDA and EPA.[149] The Cartagena Protocol on Biosafety, an international treaty that governs the transfer, handling, and use of GMOs,[150] was adopted on 29 January 2000.[151] One hundred and fifty-seven countries are members of the Protocol and many use it as a reference point for their own regulations.[152]

The legal and regulatory status of GM foods varies by country, with some nations banning or restricting them, and others permitting them with widely differing degrees of regulation.[153][154][155][156] Some countries allow the import of GM food with authorisation, but either do not allow its cultivation (Russia, Norway, Israel) or have provisions for cultivation even though no GM products are yet produced (Japan, South Korea). Most countries that do not allow GMO cultivation do permit research.[157] Some of the most marked differences occurring between the US and Europe. The US policy focuses on the product (not the process), only looks at verifiable scientific risks and uses the concept of substantial equivalence.[158] The European Union by contrast has possibly the most stringent GMO regulations in the world.[159] All GMOs, along with irradiated food, are considered “new food” and subject to extensive, case-by-case, science-based food evaluation by the European Food Safety Authority. The criteria for authorisation fall in four broad categories: “safety,” “freedom of choice,” “labelling,” and “traceability.”[160] The level of regulation in other countries that cultivate GMOs lie in between Europe and the United States.

One of the key issues concerning regulators is whether GM products should be labeled. The European Commission says that mandatory labeling and traceability are needed to allow for informed choice, avoid potential false advertising[171] and facilitate the withdrawal of products if adverse effects on health or the environment are discovered.[172] The American Medical Association[173] and the American Association for the Advancement of Science[174] say that absent scientific evidence of harm even voluntary labeling is misleading and will falsely alarm consumers. Labeling of GMO products in the marketplace is required in 64 countries.[175] Labeling can be mandatory up to a threshold GM content level (which varies between countries) or voluntary. In Canada and the US labeling of GM food is voluntary,[176] while in Europe all food (including processed food) or feed which contains greater than 0.9% of approved GMOs must be labelled.[159]

Critics have objected to the use of genetic engineering on several grounds, that include ethical, ecological and economic concerns. Many of these concerns involve GM crops and whether food produced from them is safe and what impact growing them will have on the environment. These controversies have led to litigation, international trade disputes, and protests, and to restrictive regulation of commercial products in some countries.[177]

Accusations that scientists are “playing God” and other religious issues have been ascribed to the technology from the beginning.[178] Other ethical issues raised include the patenting of life,[179] the use of intellectual property rights,[180] the level of labeling on products,[181][182] control of the food supply[183] and the objectivity of the regulatory process.[184] Although doubts have been raised,[185] economically most studies have found growing GM crops to be beneficial to farmers.[186][187][188]

Gene flow between GM crops and compatible plants, along with increased use of selective herbicides, can increase the risk of “superweeds” developing.[189] Other environmental concerns involve potential impacts on non-target organisms, including soil microbes,[190] and an increase in secondary and resistant insect pests.[191][192] Many of the environmental impacts regarding GM crops may take many years to be understood and are also evident in conventional agriculture practices.[190][193] With the commercialisation of genetically modified fish there are concerns over what the environmental consequences will be if they escape.[194]

There are three main concerns over the safety of genetically modified food: whether they may provoke an allergic reaction; whether the genes could transfer from the food into human cells; and whether the genes not approved for human consumption could outcross to other crops.[195] There is a scientific consensus[196][197][198][199] that currently available food derived from GM crops poses no greater risk to human health than conventional food,[200][201][202][203][204] but that each GM food needs to be tested on a case-by-case basis before introduction.[205][206][207] Nonetheless, members of the public are much less likely than scientists to perceive GM foods as safe.[208][209][210][211]

Genetic engineering features in many science fiction stories.[212] Frank Herbert’s novel The White Plague described the deliberate use of genetic engineering to create a pathogen which specifically killed women.[212] Another of Herbert’s creations, the Dune series of novels, uses genetic engineering to create the powerful but despised Tleilaxu.[213] Films such as The Island and Blade Runner bring the engineered creature to confront the person who created it or the being it was cloned from. Few films have informed audiences about genetic engineering, with the exception of the 1978 The Boys from Brazil and the 1993 Jurassic Park, both of which made use of a lesson, a demonstration, and a clip of scientific film.[214][215] Genetic engineering methods are weakly represented in film; Michael Clark, writing for The Wellcome Trust, calls the portrayal of genetic engineering and biotechnology “seriously distorted”[215] in films such as The 6th Day. In Clark’s view, the biotechnology is typically “given fantastic but visually arresting forms” while the science is either relegated to the background or fictionalised to suit a young audience.[215]

The literature about Biodiversity and the GE food/feed consumption has sometimes resulted in animated debate regarding the suitability of the experimental designs, the choice of the statistical methods or the public accessibility of data. Such debate, even if positive and part of the natural process of review by the scientific community, has frequently been distorted by the media and often used politically and inappropriately in anti-GE crops campaigns.

Panchin AY, Tuzhikov AI (March 2017). “Published GMO studies find no evidence of harm when corrected for multiple comparisons”. Critical Reviews in Biotechnology. 37 (2): 213217. doi:10.3109/07388551.2015.1130684. PMID26767435. Here, we show that a number of articles some of which have strongly and negatively influenced the public opinion on GM crops and even provoked political actions, such as GMO embargo, share common flaws in the statistical evaluation of the data. Having accounted for these flaws, we conclude that the data presented in these articles does not provide any substantial evidence of GMO harm.

The presented articles suggesting possible harm of GMOs received high public attention. However, despite their claims, they actually weaken the evidence for the harm and lack of substantial equivalency of studied GMOs. We emphasize that with over 1783 published articles on GMOs over the last 10 years it is expected that some of them should have reported undesired differences between GMOs and conventional crops even if no such differences exist in reality.and

Yang YT, Chen B (April 2016). “Governing GMOs in the USA: science, law and public health”. Journal of the Science of Food and Agriculture. 96 (6): 18515. doi:10.1002/jsfa.7523. PMID26536836. It is therefore not surprising that efforts to require labeling and to ban GMOs have been a growing political issue in the USA (citing Domingo and Bordonaba, 2011).

Overall, a broad scientific consensus holds that currently marketed GM food poses no greater risk than conventional food… Major national and international science and medical associations have stated that no adverse human health effects related to GMO food have been reported or substantiated in peer-reviewed literature to date.

Despite various concerns, today, the American Association for the Advancement of Science, the World Health Organization, and many independent international science organizations agree that GMOs are just as safe as other foods. Compared with conventional breeding techniques, genetic engineering is far more precise and, in most cases, less likely to create an unexpected outcome.

GM foods currently available on the international market have passed safety assessments and are not likely to present risks for human health. In addition, no effects on human health have been shown as a result of the consumption of such foods by the general population in the countries where they have been approved. Continuous application of safety assessments based on the Codex Alimentarius principles and, where appropriate, adequate post market monitoring, should form the basis for ensuring the safety of GM foods.

“Genetically modified foods and health: a second interim statement” (PDF). British Medical Association. March 2004. Retrieved 21 March 2016. In our view, the potential for GM foods to cause harmful health effects is very small and many of the concerns expressed apply with equal vigour to conventionally derived foods. However, safety concerns cannot, as yet, be dismissed completely on the basis of information currently available.

When seeking to optimise the balance between benefits and risks, it is prudent to err on the side of caution and, above all, learn from accumulating knowledge and experience. Any new technology such as genetic modification must be examined for possible benefits and risks to human health and the environment. As with all novel foods, safety assessments in relation to GM foods must be made on a case-by-case basis.

Members of the GM jury project were briefed on various aspects of genetic modification by a diverse group of acknowledged experts in the relevant subjects. The GM jury reached the conclusion that the sale of GM foods currently available should be halted and the moratorium on commercial growth of GM crops should be continued. These conclusions were based on the precautionary principle and lack of evidence of any benefit. The Jury expressed concern over the impact of GM crops on farming, the environment, food safety and other potential health effects.

The Royal Society review (2002) concluded that the risks to human health associated with the use of specific viral DNA sequences in GM plants are negligible, and while calling for caution in the introduction of potential allergens into food crops, stressed the absence of evidence that commercially available GM foods cause clinical allergic manifestations. The BMA shares the view that that there is no robust evidence to prove that GM foods are unsafe but we endorse the call for further research and surveillance to provide convincing evidence of safety and benefit.

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Genetic engineering – Wikipedia

genetic engineering | Definition, Process, & Uses …

Genetic engineering, the artificial manipulation, modification, and recombination of DNA or other nucleic acid molecules in order to modify an organism or population of organisms.

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origins of agriculture: Genetic engineering

The application of genetics to agriculture since World War II has resulted in substantial increases in the production of many crops. This has been most notable in hybrid strains of maize and grain sorghum. At the same time, crossbreeding has resulted in much

The term genetic engineering initially referred to various techniques used for the modification or manipulation of organisms through the processes of heredity and reproduction. As such, the term embraced both artificial selection and all the interventions of biomedical techniques, among them artificial insemination, in vitro fertilization (e.g., test-tube babies), cloning, and gene manipulation. In the latter part of the 20th century, however, the term came to refer more specifically to methods of recombinant DNA technology (or gene cloning), in which DNA molecules from two or more sources are combined either within cells or in vitro and are then inserted into host organisms in which they are able to propagate.

The possibility for recombinant DNA technology emerged with the discovery of restriction enzymes in 1968 by Swiss microbiologist Werner Arber. The following year American microbiologist Hamilton O. Smith purified so-called type II restriction enzymes, which were found to be essential to genetic engineering for their ability to cleave a specific site within the DNA (as opposed to type I restriction enzymes, which cleave DNA at random sites). Drawing on Smiths work, American molecular biologist Daniel Nathans helped advance the technique of DNA recombination in 197071 and demonstrated that type II enzymes could be useful in genetic studies. Genetic engineering based on recombination was pioneered in 1973 by American biochemists Stanley N. Cohen and Herbert W. Boyer, who were among the first to cut DNA into fragments, rejoin different fragments, and insert the new genes into E. coli bacteria, which then reproduced.

Most recombinant DNA technology involves the insertion of foreign genes into the plasmids of common laboratory strains of bacteria. Plasmids are small rings of DNA; they are not part of the bacteriums chromosome (the main repository of the organisms genetic information). Nonetheless, they are capable of directing protein synthesis, and, like chromosomal DNA, they are reproduced and passed on to the bacteriums progeny. Thus, by incorporating foreign DNA (for example, a mammalian gene) into a bacterium, researchers can obtain an almost limitless number of copies of the inserted gene. Furthermore, if the inserted gene is operative (i.e., if it directs protein synthesis), the modified bacterium will produce the protein specified by the foreign DNA.

A subsequent generation of genetic engineering techniques that emerged in the early 21st century centred on gene editing. Gene editing, based on a technology known as CRISPR-Cas9, allows researchers to customize a living organisms genetic sequence by making very specific changes to its DNA. Gene editing has a wide array of applications, being used for the genetic modification of crop plants and livestock and of laboratory model organisms (e.g., mice). The correction of genetic errors associated with disease in animals suggests that gene editing has potential applications in gene therapy for humans.

Genetic engineering has advanced the understanding of many theoretical and practical aspects of gene function and organization. Through recombinant DNA techniques, bacteria have been created that are capable of synthesizing human insulin, human growth hormone, alpha interferon, a hepatitis B vaccine, and other medically useful substances. Plants may be genetically adjusted to enable them to fix nitrogen, and genetic diseases can possibly be corrected by replacing dysfunctional genes with normally functioning genes. Nevertheless, special concern has been focused on such achievements for fear that they might result in the introduction of unfavourable and possibly dangerous traits into microorganisms that were previously free of theme.g., resistance to antibiotics, production of toxins, or a tendency to cause disease. Likewise, the application of gene editing in humans has raised ethical concerns, particularly regarding its potential use to alter traits such as intelligence and beauty.

In 1980 the new microorganisms created by recombinant DNA research were deemed patentable, and in 1986 the U.S. Department of Agriculture approved the sale of the first living genetically altered organisma virus, used as a pseudorabies vaccine, from which a single gene had been cut. Since then several hundred patents have been awarded for genetically altered bacteria and plants. Patents on genetically engineered and genetically modified organisms, particularly crops and other foods, however, were a contentious issue, and they remained so into the first part of the 21st century.

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genetic engineering | Definition, Process, & Uses …

Genetic Engineering Will Change Everything Forever CRISPR

Designer babies, the end of diseases, genetically modified humans that never age. Outrageous things that used to be science fiction are suddenly becoming reality. The only thing we know for sure is that things will change irreversibly.

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The best book we read about the topic: GMO Sapiens

https://goo.gl/NxFmk8

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Good Overview by Wired:http://bit.ly/1DuM4zq

timeline of computer development:http://bit.ly/1VtiJ0N

Selective breeding: http://bit.ly/29GaPVS

DNA:http://bit.ly/1rQs8Yk

Radiation research:http://bit.ly/2ad6wT1

inserting DNA snippets into organisms:http://bit.ly/2apyqbj

First genetically modified animal:http://bit.ly/2abkfYO

First GM patent:http://bit.ly/2a5cCox

chemicals produced by GMOs:http://bit.ly/29UvTbhhttp://bit.ly/2abeHwUhttp://bit.ly/2a86sBy

Flavr Savr Tomato:http://bit.ly/29YPVwN

First Human Engineering:http://bit.ly/29ZTfsf

glowing fish:http://bit.ly/29UwuJU

CRISPR:http://go.nature.com/24Nhykm

HIV cut from cells and rats with CRISPR:http://go.nature.com/1RwR1xIhttp://ti.me/1TlADSi

first human CRISPR trials fighting cancer:http://go.nature.com/28PW40r

first human CRISPR trial approved by Chinese for August 2016:http://go.nature.com/29RYNnK

genetic diseases:http://go.nature.com/2a8f7ny

pregnancies with Down Syndrome terminated:http://bit.ly/2acVyvg( 1999 European study)

CRISPR and aging:http://bit.ly/2a3NYAVhttp://bit.ly/SuomTyhttp://go.nature.com/29WpDj1http://ti.me/1R7Vus9

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Genetic Engineering Will Change Everything Forever CRISPR

Genetic Engineering: What is Genetic Engineering?

Written by Patrick Dixon

Futurist Keynote Speaker: Posts, Slides, Videos – BioTech, MedTech, Gene Therapy and Stem Cells

Video on Genetic Engineering

Genetic engineering is the alteration of genetic code by artificial means, and is therefore different from traditional selective breeding.

Huge number of other resources on this site about Genetic engineering.

Genetic engineering examples include taking the gene that programs poison in the tail of a scorpion, and combining it with a cabbage. These genetically modified cabbages kill caterpillers because they have learned to grow scorpion poison (insecticide) in their sap.

Genetic engineering also includes insertion of human genes into sheep so that they secrete alpha-1 antitrypsin in their milk – a useful substance in treating some cases of lung disease.

Genetic engineering has created a chicken with four legs and no wings.

Genetic engineering has created a goat with spider genes that creates “silk” in its milk.

Genetic engineering works because there is one language of life: human genes work in bacteria, monkey genes work in mice and earthworms. Tree genes work in bananas and frog genes work in rice. There is no limit in theory to the potential of genetic engineering.

Genetic engineering has given us the power to alter the very basis of life on earth.

Genetic engineering has been said to be no different than ancient breeding methods but this is untrue. For a start, breeding or cross-breeding, or in-breeding (for example to make pedigree dogs) all work by using the same species. In contrast genetic engineering allows us to combine fish, mouse, human and insect genes in the same person or animal.

Genetic engineering therefore has few limits – except our imagination, and our moral or ethical code.

Genetic engineering makes the whole digital revolution look nothing. Digital technology changes what we do. Genetic engineering has the power to change who we are.

Human cloning is a type of genetic engineering, but is not the same as true genetic manipulation. In human cloning, the aim is to duplicate the genes of an existing person so that an identical set is inside a human egg. The result is intended to be a cloned twin, perhaps of a dead child. Genetic engineering in its fullest form would result in the child produced having unique genes – as a result of laboratory interference, and therefore the child will not be an identikit twin.

Genetic engineering could create crops that grow in desert heat, or without fertiliser. Genetic engineering could make bananas or other fruit which contain vaccines or other medical products.

Genetic engineering is helped by the fact that it only costs $1000 to analyse someone’s genetic code (sequencing of genome) – down from $800m in 2001.

Genetic engineering is aided by techniques such as Crispr which allow scientists to swop genes between humans or between animals and humans or between animals, in a very precise and controlled way.

Genetic engineering will alter the basis of life on earth – permanently – unless controlled. This could happen if – say – mutant viruses, or bacteria, or fish or reptiles are released into the general environment.

READ FREE BOOK on Genetic Engineering – by Patrick Dixon, author of 16 books and creator of this website – read now: Chapters 1 and 2 explain basics in way which is easy to understand.

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Genetic Engineering: What is Genetic Engineering?

Genetics in fiction – Wikipedia

Aspects of genetics including mutation, hybridisation, cloning, genetic engineering, and eugenics have appeared in fiction since the 19th century.

Genetics is a young science, having started in 1900 with the rediscovery of Gregor Mendel’s study on the inheritance of traits in pea plants. During the 20th century it developed to create new sciences and technologies including molecular biology, DNA sequencing, cloning, and genetic engineering. The ethical implications were brought into focus with the eugenics movement.

Since then, many science fiction novels and films have used aspects of genetics as plot devices, often taking one of two routes: a genetic accident with disastrous consequences; or, the feasibility and desirability of a planned genetic alteration. The treatment of science in these stories has been uneven and often unrealistic. The film Gattaca did attempt to portray science accurately but was criticised by scientists.

Modern genetics began with the work of the monk Gregor Mendel in the 19th century, on the inheritance of traits in pea plants. Mendel found that visible traits, such as whether peas were round or wrinkled, were inherited discretely, rather than by blending the attributes of the two parents.[1] In 1900, Hugo de Vries and other scientists rediscovered Mendel’s research; William Bateson coined the term “genetics” for the new science, which soon investigated a wide range of phenomena including mutation (inherited changes caused by damage to the genetic material), genetic linkage (when some traits are to some extent inherited together), and hybridisation (crosses of different species).[2]

Eugenics, the production of better human beings by selective breeding, was named and advocated by Charles Darwin’s cousin, the scientist Francis Galton, in 1883. It had both a positive aspect, the breeding of more children with high intelligence and good health; and a negative aspect, aiming to suppress “race degeneration” by preventing supposedly “defective” families with attributes such as profligacy, laziness, immoral behaviour and a tendency to criminality from having children.[3][4]

Molecular biology, the interactions and regulation of genetic materials, began with the identification in 1944 of DNA as the main genetic material;[5] the genetic code and the double helix structure of DNA was determined by James Watson and Francis Crick in 1953.[6][7] DNA sequencing, the identification of an exact sequence of genetic information in an organism, was developed in 1977 by Frederick Sanger.[8]

Genetic engineering, the modification of the genetic material of a live organism, became possible in 1972 when Paul Berg created the first recombinant DNA molecules (artificially assembled genetic material) using viruses.[9]

Cloning, the production of genetically identical organisms from some chosen starting point, was shown to be practicable with the creation of Dolly the sheep from an ordinary body cell in 1996 at the Roslin Institute.[10]

Mutation and hybridisation are widely used in fiction, starting in the 19th century with science fiction works such as Mary Shelley’s 1818 novel Frankenstein and H. G. Wells’s 1896 The Island of Dr Moreau.[11]

In her 1977 Biological Themes in Modern Science Fiction, Helen Parker identified two major types of story: “genetic accident”, the uncontrolled, unexpected and disastrous alteration of a species;[12][13] and “planned genetic alteration”, whether controlled by humans or aliens, and the question of whether that would be either feasible or desirable.[12][13] In science fiction up to the 1970s, the genetic changes were brought about by radiation, breeding programmes, or manipulation with chemicals or surgery (and thus, notes Lars Schmeink, not necessarily by strictly genetic means).[13] Examples include The Island of Dr Moreau with its horrible manipulations; Aldous Huxley’s 1932 Brave New World with a breeding programme; and John Taine’s 1951 Seeds of Life, using radiation to create supermen.[13] After the discovery of the double helix and then recombinant DNA, genetic engineering became the focus for genetics in fiction, as in books like Brian Stableford’s tale of a genetically modified society in his 1998 Inherit the Earth, or Michael Marshall Smith’s story of organ farming in his 1997 Spares.[13]

Comic books have imagined mutated superhumans with extraordinary powers. The DC Universe (from 1939) imagines “metahumans”; the Marvel Universe (from 1961) calls them “mutants”, while the Wildstorm (from 1992) and Ultimate Marvel (20002015) Universes name them “posthumans”.[14] Stan Lee introduced the concept of mutants in the Marvel X-Men books in 1963; the villain Magneto declares his plan to “make Homo sapiens bow to Homo superior!”, implying that mutants will be an evolutionary step up from current humanity. Later, the books speak of an X-gene that confers powers from puberty onwards. X-men powers include telepathy, telekinesis, healing, strength, flight, time travel, and the ability to emit blasts of energy. Marvel’s god-like Celestials are later (1999) said to have visited Earth long ago and to have modified human DNA to enable mutant powers.[15]

James Blish’s 1952 novel Titan’s Daughter (in Kendell Foster Crossen’s Future Tense collection) featured stimulated polyploidy (giving organisms multiple sets of genetic material, something that can create new species in a single step), based on spontaneous polyploidy in flowering plants, to create humans with more than normal height, strength, and lifespans.[16]

Cloning, too, is a familiar plot device. In his 1990 novel Jurassic Park, Michael Crichton imagined the recovery of the complete genome of a dinosaur from fossil remains, followed by its use to recreate living animals of an extinct species.[11] Aldous Huxley’s 1931 dystopian novel Brave New World imagines the in vitro cloning of fertilised human eggs.[17][18] Huxley was influenced by J. B. S. Haldane’s 1924 non-fiction book Daedalus; or, Science and the Future, which used the Greek myth of Daedalus to symbolise the coming revolution in genetics; Haldane predicted that humans would control their own evolution through directed mutation and in vitro fertilisation.[19] Cloning was explored further in stories such as Poul Anderson’s 1953 UN-Man.[20]

Cloning is a recurring theme in science fiction films like Jurassic Park (1993), Alien Resurrection (1997), The 6th Day (2000), Resident Evil (2002), Star Wars: Episode II (2002) and The Island (2005). The process of cloning is represented variously in fiction. Many works depict the artificial creation of humans by a method of growing cells from a tissue or DNA sample; the replication may be instantaneous, or take place through slow growth of human embryos in artificial wombs. In the long-running British television series Doctor Who, the Fourth Doctor and his companion Leela were cloned in a matter of seconds from DNA samples (“The Invisible Enemy”, 1977) and thenin an apparent homage to the 1966 film Fantastic Voyageshrunk to microscopic size in order to enter the Doctor’s body to combat an alien virus. The clones in this story are short-lived, and can only survive a matter of minutes before they expire.[21] Films such as The Matrix and Star Wars: Episode II Attack of the Clones have featured human foetuses being cultured on an industrial scale in enormous tanks.[22]

Cloning humans from body parts is a common science fiction trope, one of several genetics themes parodied in Woody Allen’s 1973 comedy Sleeper, where an attempt is made to clone an assassinated dictator from his disembodied nose.[23]

Genetic engineering features in many science fiction stories.[16] Films such as The Island and Blade Runner (1982) bring the engineered creature to confront the person who created it or the being it was cloned from, a theme seen in some film versions of Frankenstein. Few films have informed audiences about genetic engineering as such, with the exception of the 1978 The Boys from Brazil and the 1993 Jurassic Park, both of which made use of a lesson, a demonstration, and a clip of scientific film.[11][24] In 1982, Frank Herbert’s novel The White Plague described the deliberate use of genetic engineering to create a pathogen which specifically killed women.[16] Another of Herbert’s creations, the Dune series of novels, starting with Dune in 1965, emphasises genetics. It combines selective breeding by a powerful sisterhood, the Bene Gesserit, to produce a supernormal male being, the Kwisatz Haderach, with the genetic engineering of the powerful but despised Tleilaxu.[25]

Genetic engineering methods are weakly represented in film; Michael Clark, writing for The Wellcome Trust, calls the portrayal of genetic engineering and biotechnology “seriously distorted”[24] in films such as Roger Spottiswoode’s 2000 The 6th Day, which makes use of the trope of a “vast clandestine laboratory … filled with row upon row of ‘blank’ human bodies kept floating in tanks of nutrient liquid or in suspended animation”. In Clark’s view, the biotechnology is typically “given fantastic but visually arresting forms” while the science is either relegated to the background or fictionalised to suit a young audience.[24]

Eugenics plays a central role in films such as Andrew Niccol’s 1997 Gattaca, the title alluding to the letters G, A, T, C for guanine, adenine, thymine, and cytosine, the four nucleobases of DNA. Genetic engineering of humans is unrestricted, resulting in genetic discrimination, loss of diversity, and adverse effects on society. The film explores the ethical implications; the production company, Sony Pictures, consulted with a gene therapy researcher, French Anderson, to ensure that the portrayal of science was realistic, and test-screened the film with the Society of Mammalian Cell Biologists and the American National Human Genome Research Institute before its release. This care did not prevent researchers from attacking the film after its release. Philim Yam of Scientific American called it “science bashing”; in Nature Kevin Davies called it a “”surprisingly pedestrian affair”; and the molecular biologist Lee Silver described the film’s extreme genetic determinism as “a straw man”.[26][27]

The geneticist Dan Koboldt observes that while science and technology play major roles in fiction, from fantasy and science fiction to thrillers, the representation of science in both literature and film is often unrealistic.[28] In Koboldt’s view, genetics in fiction is frequently oversimplified, and some myths are common and need to be debunked. For example, the Human Genome Project has not (he states) immediately led to a Gattaca world, as the relationship between genotype and phenotype is not straightforward. People do differ genetically, but only very rarely because they are missing a gene that other people have: people have different alleles of the same genes. Eye and hair colour are controlled not by one gene each, but by multiple genes. Mutations do occur, but they are rare: people are 99.99% identical genetically, the 3 million differences between any two people being dwarfed by the hundreds of millions of DNA bases which are identical; nearly all DNA variants are inherited, not acquired afresh by mutation. And, Koboldt writes, believable scientists in fiction should know their knowledge is limited.[29]

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Genetics in fiction – Wikipedia

Gene – Wikipedia

This article is about the heritable unit for transmission of biological traits. For other uses, see Gene (disambiguation).

In biology, a gene is a sequence of DNA or RNA that codes for a molecule that has a function. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism’s offspring is the basis of the inheritance of phenotypic trait. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as geneenvironment interactions. Some genetic traits are instantly visible, such as eye color or number of limbs, and some are not, such as blood type, risk for specific diseases, or the thousands of basic biochemical processes that constitute life.

Genes can acquire mutations in their sequence, leading to different variants, known as alleles, in the population. These alleles encode slightly different versions of a protein, which cause different phenotypical traits. Usage of the term “having a gene” (e.g., “good genes,” “hair colour gene”) typically refers to containing a different allele of the same, shared gene. Genes evolve due to natural selection / survival of the fittest and genetic drift of the alleles.

The concept of a gene continues to be refined as new phenomena are discovered.[1] For example, regulatory regions of a gene can be far removed from its coding regions, and coding regions can be split into several exons. Some viruses store their genome in RNA instead of DNA and some gene products are functional non-coding RNAs. Therefore, a broad, modern working definition of a gene is any discrete locus of heritable, genomic sequence which affect an organism’s traits by being expressed as a functional product or by regulation of gene expression.[2][3]

The term gene was introduced by Danish botanist, plant physiologist and geneticist Wilhelm Johannsen in 1905.[4] It is inspired by the ancient Greek: , gonos, that means offspring and procreation.

The existence of discrete inheritable units was first suggested by Gregor Mendel (18221884).[5] From 1857 to 1864, in Brno (Czech Republic), he studied inheritance patterns in 8000 common edible pea plants, tracking distinct traits from parent to offspring. He described these mathematically as 2ncombinations where n is the number of differing characteristics in the original peas. Although he did not use the term gene, he explained his results in terms of discrete inherited units that give rise to observable physical characteristics. This description prefigured Wilhelm Johannsen’s distinction between genotype (the genetic material of an organism) and phenotype (the visible traits of that organism). Mendel was also the first to demonstrate independent assortment, the distinction between dominant and recessive traits, the distinction between a heterozygote and homozygote, and the phenomenon of discontinuous inheritance.

Prior to Mendel’s work, the dominant theory of heredity was one of blending inheritance, which suggested that each parent contributed fluids to the fertilisation process and that the traits of the parents blended and mixed to produce the offspring. Charles Darwin developed a theory of inheritance he termed pangenesis, from Greek pan (“all, whole”) and genesis (“birth”) / genos (“origin”).[6][7] Darwin used the term gemmule to describe hypothetical particles that would mix during reproduction.

Mendel’s work went largely unnoticed after its first publication in 1866, but was rediscovered in the late 19th century by Hugo de Vries, Carl Correns, and Erich von Tschermak, who (claimed to have) reached similar conclusions in their own research.[8] Specifically, in 1889, Hugo de Vries published his book Intracellular Pangenesis,[9] in which he postulated that different characters have individual hereditary carriers and that inheritance of specific traits in organisms comes in particles. De Vries called these units “pangenes” (Pangens in German), after Darwin’s 1868 pangenesis theory.

Sixteen years later, in 1905, Wilhelm Johannsen introduced the term ‘gene'[4] and William Bateson that of ‘genetics'[10] while Eduard Strasburger, amongst others, still used the term ‘pangene’ for the fundamental physical and functional unit of heredity.[11]

Advances in understanding genes and inheritance continued throughout the 20th century. Deoxyribonucleic acid (DNA) was shown to be the molecular repository of genetic information by experiments in the 1940s to 1950s.[12][13] The structure of DNA was studied by Rosalind Franklin and Maurice Wilkins using X-ray crystallography, which led James D. Watson and Francis Crick to publish a model of the double-stranded DNA molecule whose paired nucleotide bases indicated a compelling hypothesis for the mechanism of genetic replication.[14][15]

In the early 1950s the prevailing view was that the genes in a chromosome acted like discrete entities, indivisible by recombination and arranged like beads on a string. The experiments of Benzer using mutants defective in the rII region of bacteriophage T4 (1955-1959) showed that individual genes have a simple linear structure and are likely to be equivalent to a linear section of DNA.[16][17]

Collectively, this body of research established the central dogma of molecular biology, which states that proteins are translated from RNA, which is transcribed from DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses. The modern study of genetics at the level of DNA is known as molecular genetics.

In 1972, Walter Fiers and his team were the first to determine the sequence of a gene: that of Bacteriophage MS2 coat protein.[18] The subsequent development of chain-termination DNA sequencing in 1977 by Frederick Sanger improved the efficiency of sequencing and turned it into a routine laboratory tool.[19] An automated version of the Sanger method was used in early phases of the Human Genome Project.[20]

The theories developed in the early 20th century to integrate Mendelian genetics with Darwinian evolution are called the modern synthesis, a term introduced by Julian Huxley.[21]

Evolutionary biologists have subsequently modified this concept, such as George C. Williams’ gene-centric view of evolution. He proposed an evolutionary concept of the gene as a unit of natural selection with the definition: “that which segregates and recombines with appreciable frequency.”[22]:24 In this view, the molecular gene transcribes as a unit, and the evolutionary gene inherits as a unit. Related ideas emphasizing the centrality of genes in evolution were popularized by Richard Dawkins.[23][24]

The vast majority of organisms encode their genes in long strands of DNA (deoxyribonucleic acid). DNA consists of a chain made from four types of nucleotide subunits, each composed of: a five-carbon sugar (2-deoxyribose), a phosphate group, and one of the four bases adenine, cytosine, guanine, and thymine.[25]:2.1

Two chains of DNA twist around each other to form a DNA double helix with the phosphate-sugar backbone spiralling around the outside, and the bases pointing inwards with adenine base pairing to thymine and guanine to cytosine. The specificity of base pairing occurs because adenine and thymine align to form two hydrogen bonds, whereas cytosine and guanine form three hydrogen bonds. The two strands in a double helix must therefore be complementary, with their sequence of bases matching such that the adenines of one strand are paired with the thymines of the other strand, and so on.[25]:4.1

Due to the chemical composition of the pentose residues of the bases, DNA strands have directionality. One end of a DNA polymer contains an exposed hydroxyl group on the deoxyribose; this is known as the 3’end of the molecule. The other end contains an exposed phosphate group; this is the 5’end. The two strands of a double-helix run in opposite directions. Nucleic acid synthesis, including DNA replication and transcription occurs in the 5’3’direction, because new nucleotides are added via a dehydration reaction that uses the exposed 3’hydroxyl as a nucleophile.[26]:27.2

The expression of genes encoded in DNA begins by transcribing the gene into RNA, a second type of nucleic acid that is very similar to DNA, but whose monomers contain the sugar ribose rather than deoxyribose. RNA also contains the base uracil in place of thymine. RNA molecules are less stable than DNA and are typically single-stranded. Genes that encode proteins are composed of a series of three-nucleotide sequences called codons, which serve as the “words” in the genetic “language”. The genetic code specifies the correspondence during protein translation between codons and amino acids. The genetic code is nearly the same for all known organisms.[25]:4.1

The total complement of genes in an organism or cell is known as its genome, which may be stored on one or more chromosomes. A chromosome consists of a single, very long DNA helix on which thousands of genes are encoded.[25]:4.2 The region of the chromosome at which a particular gene is located is called its locus. Each locus contains one allele of a gene; however, members of a population may have different alleles at the locus, each with a slightly different gene sequence.

The majority of eukaryotic genes are stored on a set of large, linear chromosomes. The chromosomes are packed within the nucleus in complex with storage proteins called histones to form a unit called a nucleosome. DNA packaged and condensed in this way is called chromatin.[25]:4.2 The manner in which DNA is stored on the histones, as well as chemical modifications of the histone itself, regulate whether a particular region of DNA is accessible for gene expression. In addition to genes, eukaryotic chromosomes contain sequences involved in ensuring that the DNA is copied without degradation of end regions and sorted into daughter cells during cell division: replication origins, telomeres and the centromere.[25]:4.2 Replication origins are the sequence regions where DNA replication is initiated to make two copies of the chromosome. Telomeres are long stretches of repetitive sequence that cap the ends of the linear chromosomes and prevent degradation of coding and regulatory regions during DNA replication. The length of the telomeres decreases each time the genome is replicated and has been implicated in the aging process.[28] The centromere is required for binding spindle fibres to separate sister chromatids into daughter cells during cell division.[25]:18.2

Prokaryotes (bacteria and archaea) typically store their genomes on a single large, circular chromosome. Similarly, some eukaryotic organelles contain a remnant circular chromosome with a small number of genes.[25]:14.4 Prokaryotes sometimes supplement their chromosome with additional small circles of DNA called plasmids, which usually encode only a few genes and are transferable between individuals. For example, the genes for antibiotic resistance are usually encoded on bacterial plasmids and can be passed between individual cells, even those of different species, via horizontal gene transfer.[29]

Whereas the chromosomes of prokaryotes are relatively gene-dense, those of eukaryotes often contain regions of DNA that serve no obvious function. Simple single-celled eukaryotes have relatively small amounts of such DNA, whereas the genomes of complex multicellular organisms, including humans, contain an absolute majority of DNA without an identified function.[30] This DNA has often been referred to as “junk DNA”. However, more recent analyses suggest that, although protein-coding DNA makes up barely 2% of the human genome, about 80% of the bases in the genome may be expressed, so the term “junk DNA” may be a misnomer.[3]

The structure of a gene consists of many elements of which the actual protein coding sequence is often only a small part. These include DNA regions that are not transcribed as well as untranslated regions of the RNA.

Flanking the open reading frame, genes contain a regulatory sequence that is required for their expression. First, genes require a promoter sequence. The promoter is recognized and bound by transcription factors and RNA polymerase to initiate transcription.[25]:7.1 The recognition typically occurs as a consensus sequence like the TATA box. A gene can have more than one promoter, resulting in messenger RNAs (mRNA) that differ in how far they extend in the 5’end.[32] Highly transcribed genes have “strong” promoter sequences that form strong associations with transcription factors, thereby initiating transcription at a high rate. Others genes have “weak” promoters that form weak associations with transcription factors and initiate transcription less frequently.[25]:7.2 Eukaryotic promoter regions are much more complex and difficult to identify than prokaryotic promoters.[25]:7.3

Additionally, genes can have regulatory regions many kilobases upstream or downstream of the open reading frame that alter expression. These act by binding to transcription factors which then cause the DNA to loop so that the regulatory sequence (and bound transcription factor) become close to the RNA polymerase binding site.[33] For example, enhancers increase transcription by binding an activator protein which then helps to recruit the RNA polymerase to the promoter; conversely silencers bind repressor proteins and make the DNA less available for RNA polymerase.[34]

The transcribed pre-mRNA contains untranslated regions at both ends which contain a ribosome binding site, terminator and start and stop codons.[35] In addition, most eukaryotic open reading frames contain untranslated introns which are removed before the exons are translated. The sequences at the ends of the introns, dictate the splice sites to generate the final mature mRNA which encodes the protein or RNA product.[36]

Many prokaryotic genes are organized into operons, with multiple protein-coding sequences that are transcribed as a unit.[37][38] The genes in an operon are transcribed as a continuous messenger RNA, referred to as a polycistronic mRNA. The term cistron in this context is equivalent to gene. The transcription of an operons mRNA is often controlled by a repressor that can occur in an active or inactive state depending on the presence of certain specific metabolites.[39] When active, the repressor binds to a DNA sequence at the beginning of the operon, called the operator region, and represses transcription of the operon; when the repressor is inactive transcription of the operon can occur (see e.g. Lac operon). The products of operon genes typically have related functions and are involved in the same regulatory network.[25]:7.3

Defining exactly what section of a DNA sequence comprises a gene is difficult.[1] Regulatory regions of a gene such as enhancers do not necessarily have to be close to the coding sequence on the linear molecule because the intervening DNA can be looped out to bring the gene and its regulatory region into proximity. Similarly, a gene’s introns can be much larger than its exons. Regulatory regions can even be on entirely different chromosomes and operate in trans to allow regulatory regions on one chromosome to come in contact with target genes on another chromosome.[40][41]

Early work in molecular genetics suggested the concept that one gene makes one protein. This concept (originally called the one gene-one enzyme hypothesis) emerged from an influential 1941 paper by George Beadle and Edward Tatum on experiments with mutants of the fungus Neurospora crassa.[42] Norman Horowitz, an early colleague on the Neurospora research, reminisced in 2004 that these experiments founded the science of what Beadle and Tatum called biochemical genetics. In actuality they proved to be the opening gun in what became molecular genetics and all the developments that have followed from that.[43] The one gene-one protein concept has been refined since the discovery of genes that can encode multiple proteins by alternative splicing and coding sequences split in short section across the genome whose mRNAs are concatenated by trans-splicing.[3][44][45]

A broad operational definition is sometimes used to encompass the complexity of these diverse phenomena, where a gene is defined as a union of genomic sequences encoding a coherent set of potentially overlapping functional products.[10] This definition categorizes genes by their functional products (proteins or RNA) rather than their specific DNA loci, with regulatory elements classified as gene-associated regions.[10]

In all organisms, two steps are required to read the information encoded in a gene’s DNA and produce the protein it specifies. First, the gene’s DNA is transcribed to messenger RNA (mRNA).[25]:6.1 Second, that mRNA is translated to protein.[25]:6.2 RNA-coding genes must still go through the first step, but are not translated into protein.[46] The process of producing a biologically functional molecule of either RNA or protein is called gene expression, and the resulting molecule is called a gene product.

The nucleotide sequence of a gene’s DNA specifies the amino acid sequence of a protein through the genetic code. Sets of three nucleotides, known as codons, each correspond to a specific amino acid.[25]:6 The principle that three sequential bases of DNA code for each amino acid was demonstrated in 1961 using frameshift mutations in the rIIB gene of bacteriophage T4[47] (see Crick, Brenner et al. experiment).

Additionally, a “start codon”, and three “stop codons” indicate the beginning and end of the protein coding region. There are 64possible codons (four possible nucleotides at each of three positions, hence 43possible codons) and only 20standard amino acids; hence the code is redundant and multiple codons can specify the same amino acid. The correspondence between codons and amino acids is nearly universal among all known living organisms.[48]

Transcription produces a single-stranded RNA molecule known as messenger RNA, whose nucleotide sequence is complementary to the DNA from which it was transcribed.[25]:6.1 The mRNA acts as an intermediate between the DNA gene and its final protein product. The gene’s DNA is used as a template to generate a complementary mRNA. The mRNA matches the sequence of the gene’s DNA coding strand because it is synthesised as the complement of the template strand. Transcription is performed by an enzyme called an RNA polymerase, which reads the template strand in the 3′ to 5’direction and synthesizes the RNA from 5′ to 3′. To initiate transcription, the polymerase first recognizes and binds a promoter region of the gene. Thus, a major mechanism of gene regulation is the blocking or sequestering the promoter region, either by tight binding by repressor molecules that physically block the polymerase, or by organizing the DNA so that the promoter region is not accessible.[25]:7

In prokaryotes, transcription occurs in the cytoplasm; for very long transcripts, translation may begin at the 5’end of the RNA while the 3’end is still being transcribed. In eukaryotes, transcription occurs in the nucleus, where the cell’s DNA is stored. The RNA molecule produced by the polymerase is known as the primary transcript and undergoes post-transcriptional modifications before being exported to the cytoplasm for translation. One of the modifications performed is the splicing of introns which are sequences in the transcribed region that do not encode protein. Alternative splicing mechanisms can result in mature transcripts from the same gene having different sequences and thus coding for different proteins. This is a major form of regulation in eukaryotic cells and also occurs in some prokaryotes.[25]:7.5[49]

Translation is the process by which a mature mRNA molecule is used as a template for synthesizing a new protein.[25]:6.2 Translation is carried out by ribosomes, large complexes of RNA and protein responsible for carrying out the chemical reactions to add new amino acids to a growing polypeptide chain by the formation of peptide bonds. The genetic code is read three nucleotides at a time, in units called codons, via interactions with specialized RNA molecules called transfer RNA (tRNA). Each tRNA has three unpaired bases known as the anticodon that are complementary to the codon it reads on the mRNA. The tRNA is also covalently attached to the amino acid specified by the complementary codon. When the tRNA binds to its complementary codon in an mRNA strand, the ribosome attaches its amino acid cargo to the new polypeptide chain, which is synthesized from amino terminus to carboxyl terminus. During and after synthesis, most new proteins must fold to their active three-dimensional structure before they can carry out their cellular functions.[25]:3

Genes are regulated so that they are expressed only when the product is needed, since expression draws on limited resources.[25]:7 A cell regulates its gene expression depending on its external environment (e.g. available nutrients, temperature and other stresses), its internal environment (e.g. cell division cycle, metabolism, infection status), and its specific role if in a multicellular organism. Gene expression can be regulated at any step: from transcriptional initiation, to RNA processing, to post-translational modification of the protein. The regulation of lactose metabolism genes in E. coli (lac operon) was the first such mechanism to be described in 1961.[50]

A typical protein-coding gene is first copied into RNA as an intermediate in the manufacture of the final protein product.[25]:6.1 In other cases, the RNA molecules are the actual functional products, as in the synthesis of ribosomal RNA and transfer RNA. Some RNAs known as ribozymes are capable of enzymatic function, and microRNA has a regulatory role. The DNA sequences from which such RNAs are transcribed are known as non-coding RNA genes.[46]

Some viruses store their entire genomes in the form of RNA, and contain no DNA at all.[51][52] Because they use RNA to store genes, their cellular hosts may synthesize their proteins as soon as they are infected and without the delay in waiting for transcription.[53] On the other hand, RNA retroviruses, such as HIV, require the reverse transcription of their genome from RNA into DNA before their proteins can be synthesized. RNA-mediated epigenetic inheritance has also been observed in plants and very rarely in animals.[54]

Organisms inherit their genes from their parents. Asexual organisms simply inherit a complete copy of their parent’s genome. Sexual organisms have two copies of each chromosome because they inherit one complete set from each parent.[25]:1

According to Mendelian inheritance, variations in an organism’s phenotype (observable physical and behavioral characteristics) are due in part to variations in its genotype (particular set of genes). Each gene specifies a particular trait with different sequence of a gene (alleles) giving rise to different phenotypes. Most eukaryotic organisms (such as the pea plants Mendel worked on) have two alleles for each trait, one inherited from each parent.[25]:20

Alleles at a locus may be dominant or recessive; dominant alleles give rise to their corresponding phenotypes when paired with any other allele for the same trait, whereas recessive alleles give rise to their corresponding phenotype only when paired with another copy of the same allele. If you know the genotypes of the organisms, you can determine which alleles are dominant and which are recessive. For example, if the allele specifying tall stems in pea plants is dominant over the allele specifying short stems, then pea plants that inherit one tall allele from one parent and one short allele from the other parent will also have tall stems. Mendel’s work demonstrated that alleles assort independently in the production of gametes, or germ cells, ensuring variation in the next generation. Although Mendelian inheritance remains a good model for many traits determined by single genes (including a number of well-known genetic disorders) it does not include the physical processes of DNA replication and cell division.[55][56]

The growth, development, and reproduction of organisms relies on cell division; the process by which a single cell divides into two usually identical daughter cells. This requires first making a duplicate copy of every gene in the genome in a process called DNA replication.[25]:5.2 The copies are made by specialized enzymes known as DNA polymerases, which “read” one strand of the double-helical DNA, known as the template strand, and synthesize a new complementary strand. Because the DNA double helix is held together by base pairing, the sequence of one strand completely specifies the sequence of its complement; hence only one strand needs to be read by the enzyme to produce a faithful copy. The process of DNA replication is semiconservative; that is, the copy of the genome inherited by each daughter cell contains one original and one newly synthesized strand of DNA.[25]:5.2

The rate of DNA replication in living cells was first measured as the rate of phage T4 DNA elongation in phage-infected E. coli and found to be impressively rapid.[57] During the period of exponential DNA increase at 37C, the rate of elongation was 749 nucleotides per second.

After DNA replication is complete, the cell must physically separate the two copies of the genome and divide into two distinct membrane-bound cells.[25]:18.2 In prokaryotes(bacteria and archaea) this usually occurs via a relatively simple process called binary fission, in which each circular genome attaches to the cell membrane and is separated into the daughter cells as the membrane invaginates to split the cytoplasm into two membrane-bound portions. Binary fission is extremely fast compared to the rates of cell division in eukaryotes. Eukaryotic cell division is a more complex process known as the cell cycle; DNA replication occurs during a phase of this cycle known as S phase, whereas the process of segregating chromosomes and splitting the cytoplasm occurs during M phase.[25]:18.1

The duplication and transmission of genetic material from one generation of cells to the next is the basis for molecular inheritance, and the link between the classical and molecular pictures of genes. Organisms inherit the characteristics of their parents because the cells of the offspring contain copies of the genes in their parents’ cells. In asexually reproducing organisms, the offspring will be a genetic copy or clone of the parent organism. In sexually reproducing organisms, a specialized form of cell division called meiosis produces cells called gametes or germ cells that are haploid, or contain only one copy of each gene.[25]:20.2 The gametes produced by females are called eggs or ova, and those produced by males are called sperm. Two gametes fuse to form a diploid fertilized egg, a single cell that has two sets of genes, with one copy of each gene from the mother and one from the father.[25]:20

During the process of meiotic cell division, an event called genetic recombination or crossing-over can sometimes occur, in which a length of DNA on one chromatid is swapped with a length of DNA on the corresponding homologous non-sister chromatid. This can result in reassortment of otherwise linked alleles.[25]:5.5 The Mendelian principle of independent assortment asserts that each of a parent’s two genes for each trait will sort independently into gametes; which allele an organism inherits for one trait is unrelated to which allele it inherits for another trait. This is in fact only true for genes that do not reside on the same chromosome, or are located very far from one another on the same chromosome. The closer two genes lie on the same chromosome, the more closely they will be associated in gametes and the more often they will appear together (known as genetic linkage).[58] Genes that are very close are essentially never separated because it is extremely unlikely that a crossover point will occur between them.[58]

DNA replication is for the most part extremely accurate, however errors (mutations) do occur.[25]:7.6 The error rate in eukaryotic cells can be as low as 108 per nucleotide per replication,[59][60] whereas for some RNA viruses it can be as high as 103.[61] This means that each generation, each human genome accumulates 12 new mutations.[61] Small mutations can be caused by DNA replication and the aftermath of DNA damage and include point mutations in which a single base is altered and frameshift mutations in which a single base is inserted or deleted. Either of these mutations can change the gene by missense (change a codon to encode a different amino acid) or nonsense (a premature stop codon).[62] Larger mutations can be caused by errors in recombination to cause chromosomal abnormalities including the duplication, deletion, rearrangement or inversion of large sections of a chromosome. Additionally, DNA repair mechanisms can introduce mutational errors when repairing physical damage to the molecule. The repair, even with mutation, is more important to survival than restoring an exact copy, for example when repairing double-strand breaks.[25]:5.4

When multiple different alleles for a gene are present in a species’s population it is called polymorphic. Most different alleles are functionally equivalent, however some alleles can give rise to different phenotypic traits. A gene’s most common allele is called the wild type, and rare alleles are called mutants. The genetic variation in relative frequencies of different alleles in a population is due to both natural selection and genetic drift.[63] The wild-type allele is not necessarily the ancestor of less common alleles, nor is it necessarily fitter.

Most mutations within genes are neutral, having no effect on the organism’s phenotype (silent mutations). Some mutations do not change the amino acid sequence because multiple codons encode the same amino acid (synonymous mutations). Other mutations can be neutral if they lead to amino acid sequence changes, but the protein still functions similarly with the new amino acid (e.g. conservative mutations). Many mutations, however, are deleterious or even lethal, and are removed from populations by natural selection. Genetic disorders are the result of deleterious mutations and can be due to spontaneous mutation in the affected individual, or can be inherited. Finally, a small fraction of mutations are beneficial, improving the organism’s fitness and are extremely important for evolution, since their directional selection leads to adaptive evolution.[25]:7.6

Genes with a most recent common ancestor, and thus a shared evolutionary ancestry, are known as homologs.[64] These genes appear either from gene duplication within an organism’s genome, where they are known as paralogous genes, or are the result of divergence of the genes after a speciation event, where they are known as orthologous genes,[25]:7.6 and often perform the same or similar functions in related organisms. It is often assumed that the functions of orthologous genes are more similar than those of paralogous genes, although the difference is minimal.[65][66]

The relationship between genes can be measured by comparing the sequence alignment of their DNA.[25]:7.6 The degree of sequence similarity between homologous genes is called conserved sequence. Most changes to a gene’s sequence do not affect its function and so genes accumulate mutations over time by neutral molecular evolution. Additionally, any selection on a gene will cause its sequence to diverge at a different rate. Genes under stabilizing selection are constrained and so change more slowly whereas genes under directional selection change sequence more rapidly.[67] The sequence differences between genes can be used for phylogenetic analyses to study how those genes have evolved and how the organisms they come from are related.[68][69]

The most common source of new genes in eukaryotic lineages is gene duplication, which creates copy number variation of an existing gene in the genome.[70][71] The resulting genes (paralogs) may then diverge in sequence and in function. Sets of genes formed in this way compose a gene family. Gene duplications and losses within a family are common and represent a major source of evolutionary biodiversity.[72] Sometimes, gene duplication may result in a nonfunctional copy of a gene, or a functional copy may be subject to mutations that result in loss of function; such nonfunctional genes are called pseudogenes.[25]:7.6

“Orphan” genes, whose sequence shows no similarity to existing genes, are less common than gene duplicates. Estimates of the number of genes with no homologs outside humans range from 18[73] to 60.[74] Two primary sources of orphan protein-coding genes are gene duplication followed by extremely rapid sequence change, such that the original relationship is undetectable by sequence comparisons, and de novo conversion of a previously non-coding sequence into a protein-coding gene.[75] De novo genes are typically shorter and simpler in structure than most eukaryotic genes, with few if any introns.[70] Over long evolutionary time periods, de novo gene birth may be responsible for a significant fraction of taxonomically-restricted gene families.[76]

Horizontal gene transfer refers to the transfer of genetic material through a mechanism other than reproduction. This mechanism is a common source of new genes in prokaryotes, sometimes thought to contribute more to genetic variation than gene duplication.[77] It is a common means of spreading antibiotic resistance, virulence, and adaptive metabolic functions.[29][78] Although horizontal gene transfer is rare in eukaryotes, likely examples have been identified of protist and alga genomes containing genes of bacterial origin.[79][80]

The genome is the total genetic material of an organism and includes both the genes and non-coding sequences.[81]

The genome size, and the number of genes it encodes varies widely between organisms. The smallest genomes occur in viruses,[90] and viroids (which act as a single non-coding RNA gene).[91] Conversely, plants can have extremely large genomes,[92] with rice containing >46,000 protein-coding genes.[93] The total number of protein-coding genes (the Earth’s proteome) is estimated to be 5million sequences.[94]

Although the number of base-pairs of DNA in the human genome has been known since the 1960s, the estimated number of genes has changed over time as definitions of genes, and methods of detecting them have been refined. Initial theoretical predictions of the number of human genes were as high as 2,000,000.[95] Early experimental measures indicated there to be 50,000100,000 transcribed genes (expressed sequence tags).[96] Subsequently, the sequencing in the Human Genome Project indicated that many of these transcripts were alternative variants of the same genes, and the total number of protein-coding genes was revised down to ~20,000[89] with 13 genes encoded on the mitochondrial genome.[87] With the GENCODE annotation project, that estimate has continued to fall to 19,000.[97] Of the human genome, only 12% consists of protein-coding genes,[98] with the remainder being ‘noncoding’ DNA such as introns, retrotransposons, and noncoding RNAs.[98][99] Every multicellular organism has all its genes in each cell of its body but not every gene functions in every cell .

Essential genes are the set of genes thought to be critical for an organism’s survival.[101] This definition assumes the abundant availability of all relevant nutrients and the absence of environmental stress. Only a small portion of an organism’s genes are essential. In bacteria, an estimated 250400 genes are essential for Escherichia coli and Bacillus subtilis, which is less than 10% of their genes.[102][103][104] Half of these genes are orthologs in both organisms and are largely involved in protein synthesis.[104] In the budding yeast Saccharomyces cerevisiae the number of essential genes is slightly higher, at 1000 genes (~20% of their genes).[105] Although the number is more difficult to measure in higher eukaryotes, mice and humans are estimated to have around 2000 essential genes (~10% of their genes).[106] The synthetic organism, Syn 3, has a minimal genome of 473 essential genes and quasi-essential genes (necessary for fast growth), although 149 have unknown function.[100]

Essential genes include Housekeeping genes (critical for basic cell functions)[107] as well as genes that are expressed at different times in the organisms development or life cycle.[108] Housekeeping genes are used as experimental controls when analysing gene expression, since they are constitutively expressed at a relatively constant level.

Gene nomenclature has been established by the HUGO Gene Nomenclature Committee (HGNC) for each known human gene in the form of an approved gene name and symbol (short-form abbreviation), which can be accessed through a database maintained by HGNC. Symbols are chosen to be unique, and each gene has only one symbol (although approved symbols sometimes change). Symbols are preferably kept consistent with other members of a gene family and with homologs in other species, particularly the mouse due to its role as a common model organism.[109]

Genetic engineering is the modification of an organism’s genome through biotechnology. Since the 1970s, a variety of techniques have been developed to specifically add, remove and edit genes in an organism.[110] Recently developed genome engineering techniques use engineered nuclease enzymes to create targeted DNA repair in a chromosome to either disrupt or edit a gene when the break is repaired.[111][112][113][114] The related term synthetic biology is sometimes used to refer to extensive genetic engineering of an organism.[115]

Genetic engineering is now a routine research tool with model organisms. For example, genes are easily added to bacteria[116] and lineages of knockout mice with a specific gene’s function disrupted are used to investigate that gene’s function.[117][118] Many organisms have been genetically modified for applications in agriculture, industrial biotechnology, and medicine.

For multicellular organisms, typically the embryo is engineered which grows into the adult genetically modified organism.[119] However, the genomes of cells in an adult organism can be edited using gene therapy techniques to treat genetic diseases.

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Gene – Wikipedia

Stem cell

STEM CELL SUPPLEMENTS

Stem cells are cells with the ability to divide for indefinite periods in culture and to give rise to specialized cells.

Stem Cell Supplements are developed based on the merits of stem cells and they are applied for degenerative diseases treatments and to stimulate the formation of all the different tissues of the body: muscle, cartilage, tendon, ligament, bone, blood,nerve, organs, etc. Stem Cell Supplements bring essential health & antiaging benefits by providing necessary elements to the body to improve cellular rejuvenation, organ regeneration and tissue healing.

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Stem cell

Stem Cell Treatment | Arizona | Stem Cell Rejuvenation Center

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Please Note: Although we have supplied links to the research journals above on the use of stem cells for specific conditions, we are not saying that any of these studies would relate to your particular condition, nor that it would even be an effective treatment. OurAutologousStem Cell Therapy is not an FDA approved treatment for any condition. We provide stem cell therapy (less than manipulated) as a service &as a practice of medicine only. Please see theFAQ pagefor more information. Thesejournal articlesare for educational purposes only &are not intended to be used to sell or promote our therapy.

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Stem Cell Treatment | Arizona | Stem Cell Rejuvenation Center

Stem cell – Wikipedia

Stem cells are biological cells that can differentiate into other types of cells and can divide to produce more of the same type of stem cells. They are always and only found in the multicellular organisms.

In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues. In a developing embryo, stem cells can differentiate into all the specialized cellsectoderm, endoderm and mesoderm (see induced pluripotent stem cells)but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.

There are three known accessible sources of autologous adult stem cells in humans:

Stem cells can also be taken from umbilical cord blood just after birth. Of all stem cell types, autologous harvesting involves the least risk. By definition, autologous cells are obtained from one’s own body, just as one may bank his or her own blood for elective surgical procedures.

Adult stem cells are frequently used in various medical therapies (e.g., bone marrow transplantation). Stem cells can now be artificially grown and transformed (differentiated) into specialized cell types with characteristics consistent with cells of various tissues such as muscles or nerves. Embryonic cell lines and autologous embryonic stem cells generated through somatic cell nuclear transfer or dedifferentiation have also been proposed as promising candidates for future therapies.[2] Research into stem cells grew out of findings by Ernest A. McCulloch and James E. Till at the University of Toronto in the 1960s.[3][4]

The classical definition of a stem cell requires that it possesses two properties:

Two mechanisms exist to ensure that a stem cell population is maintained:

1. Obligatory asymmetric replication: a stem cell divides into one mother cell that is identical to the original stem cell, and another daughter cell that is differentiated.

When a stem cell self-renews it divides and does not disrupt the undifferentiated state. This self-renewal demands control of cell cycle as well as upkeep of multipotency or pluripotency, which all depends on the stem cell.[5]

2. Stochastic differentiation: when one stem cell develops into two differentiated daughter cells, another stem cell undergoes mitosis and produces two stem cells identical to the original.

Potency specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell.[6]

In practice, stem cells are identified by whether they can regenerate tissue. For example, the defining test for bone marrow or hematopoietic stem cells (HSCs) is the ability to transplant the cells and save an individual without HSCs. This demonstrates that the cells can produce new blood cells over a long term. It should also be possible to isolate stem cells from the transplanted individual, which can themselves be transplanted into another individual without HSCs, demonstrating that the stem cell was able to self-renew.

Properties of stem cells can be illustrated in vitro, using methods such as clonogenic assays, in which single cells are assessed for their ability to differentiate and self-renew.[9][10] Stem cells can also be isolated by their possession of a distinctive set of cell surface markers. However, in vitro culture conditions can alter the behavior of cells, making it unclear whether the cells shall behave in a similar manner in vivo. There is considerable debate as to whether some proposed adult cell populations are truly stem cells.[11]

Embryonic stem cells (ESCs) are the cells of the inner cell mass of a blastocyst, an early-stage embryo.[12] Human embryos reach the blastocyst stage 45 days post fertilization, at which time they consist of 50150 cells. ESCs are pluripotent and give rise during development to all derivatives of the three primary germ layers: ectoderm, endoderm and mesoderm. In other words, they can develop into each of the more than 200 cell types of the adult body when given sufficient and necessary stimulation for a specific cell type. They do not contribute to the extra-embryonic membranes or the placenta.

During embryonic development these inner cell mass cells continuously divide and become more specialized. For example, a portion of the ectoderm in the dorsal part of the embryo specializes as ‘neurectoderm’, which will become the future central nervous system.[13] Later in development, neurulation causes the neurectoderm to form the neural tube. At the neural tube stage, the anterior portion undergoes encephalization to generate or ‘pattern’ the basic form of the brain. At this stage of development, the principal cell type of the CNS is considered a neural stem cell. These neural stem cells are pluripotent, as they can generate a large diversity of many different neuron types, each with unique gene expression, morphological, and functional characteristics. The process of generating neurons from stem cells is called neurogenesis. One prominent example of a neural stem cell is the radial glial cell, so named because it has a distinctive bipolar morphology with highly elongated processes spanning the thickness of the neural tube wall, and because historically it shared some glial characteristics, most notably the expression of glial fibrillary acidic protein (GFAP).[14][15] The radial glial cell is the primary neural stem cell of the developing vertebrate CNS, and its cell body resides in the ventricular zone, adjacent to the developing ventricular system. Neural stem cells are committed to the neuronal lineages (neurons, astrocytes, and oligodendrocytes), and thus their potency is restricted.[13]

Nearly all research to date has made use of mouse embryonic stem cells (mES) or human embryonic stem cells (hES) derived from the early inner cell mass. Both have the essential stem cell characteristics, yet they require very different environments in order to maintain an undifferentiated state. Mouse ES cells are grown on a layer of gelatin as an extracellular matrix (for support) and require the presence of leukemia inhibitory factor (LIF) in serum media. A drug cocktail containing inhibitors to GSK3B and the MAPK/ERK pathway, called 2i, has also been shown to maintain pluripotency in stem cell culture.[16] Human ESCs are grown on a feeder layer of mouse embryonic fibroblasts and require the presence of basic fibroblast growth factor (bFGF or FGF-2).[17] Without optimal culture conditions or genetic manipulation,[18] embryonic stem cells will rapidly differentiate.

A human embryonic stem cell is also defined by the expression of several transcription factors and cell surface proteins. The transcription factors Oct-4, Nanog, and Sox2 form the core regulatory network that ensures the suppression of genes that lead to differentiation and the maintenance of pluripotency.[19] The cell surface antigens most commonly used to identify hES cells are the glycolipids stage specific embryonic antigen 3 and 4 and the keratan sulfate antigens Tra-1-60 and Tra-1-81. By using human embryonic stem cells to produce specialized cells like nerve cells or heart cells in the lab, scientists can gain access to adult human cells without taking tissue from patients. They can then study these specialized adult cells in detail to try and catch complications of diseases, or to study cells reactions to potentially new drugs. The molecular definition of a stem cell includes many more proteins and continues to be a topic of research.[20]

There are currently no approved treatments using embryonic stem cells. The first human trial was approved by the US Food and Drug Administration in January 2009.[21] However, the human trial was not initiated until October 13, 2010 in Atlanta for spinal cord injury research. On November 14, 2011 the company conducting the trial (Geron Corporation) announced that it will discontinue further development of its stem cell programs.[22] ES cells, being pluripotent cells, require specific signals for correct differentiationif injected directly into another body, ES cells will differentiate into many different types of cells, causing a teratoma. Differentiating ES cells into usable cells while avoiding transplant rejection are just a few of the hurdles that embryonic stem cell researchers still face.[23] Due to ethical considerations, many nations currently have moratoria or limitations on either human ES cell research or the production of new human ES cell lines. Because of their combined abilities of unlimited expansion and pluripotency, embryonic stem cells remain a theoretically potential source for regenerative medicine and tissue replacement after injury or disease.[24]

Human embryonic stem cell colony on mouse embryonic fibroblast feeder layer

The primitive stem cells located in the organs of fetuses are referred to as fetal stem cells.[25]There are two types of fetal stem cells:

Adult stem cells, also called somatic (from Greek , “of the body”) stem cells, are stem cells which maintain and repair the tissue in which they are found.[27] They can be found in children, as well as adults.[28]

Pluripotent adult stem cells are rare and generally small in number, but they can be found in umbilical cord blood and other tissues.[29] Bone marrow is a rich source of adult stem cells,[30] which have been used in treating several conditions including liver cirrhosis,[31] chronic limb ischemia [32] and endstage heart failure.[33] The quantity of bone marrow stem cells declines with age and is greater in males than females during reproductive years.[34] Much adult stem cell research to date has aimed to characterize their potency and self-renewal capabilities.[35] DNA damage accumulates with age in both stem cells and the cells that comprise the stem cell environment. This accumulation is considered to be responsible, at least in part, for increasing stem cell dysfunction with aging (see DNA damage theory of aging).[36]

Most adult stem cells are lineage-restricted (multipotent) and are generally referred to by their tissue origin (mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, dental pulp stem cell, etc.).[37][38] Muse cells (multi-lineage differentiating stress enduring cells) are a recently discovered pluripotent stem cell type found in multiple adult tissues, including adipose, dermal fibroblasts, and bone marrow. While rare, muse cells are identifiable by their expression of SSEA-3, a marker for undifferentiated stem cells, and general mesenchymal stem cells markers such as CD105. When subjected to single cell suspension culture, the cells will generate clusters that are similar to embryoid bodies in morphology as well as gene expression, including canonical pluripotency markers Oct4, Sox2, and Nanog.[39]

Adult stem cell treatments have been successfully used for many years to treat leukemia and related bone/blood cancers through bone marrow transplants.[40] Adult stem cells are also used in veterinary medicine to treat tendon and ligament injuries in horses.[41]

The use of adult stem cells in research and therapy is not as controversial as the use of embryonic stem cells, because the production of adult stem cells does not require the destruction of an embryo. Additionally, in instances where adult stem cells are obtained from the intended recipient (an autograft), the risk of rejection is essentially non-existent. Consequently, more US government funding is being provided for adult stem cell research.[42]

Multipotent stem cells are also found in amniotic fluid. These stem cells are very active, expand extensively without feeders and are not tumorigenic. Amniotic stem cells are multipotent and can differentiate in cells of adipogenic, osteogenic, myogenic, endothelial, hepatic and also neuronal lines.[43]Amniotic stem cells are a topic of active research.

Use of stem cells from amniotic fluid overcomes the ethical objections to using human embryos as a source of cells. Roman Catholic teaching forbids the use of embryonic stem cells in experimentation; accordingly, the Vatican newspaper “Osservatore Romano” called amniotic stem cells “the future of medicine”.[44]

It is possible to collect amniotic stem cells for donors or for autologuous use: the first US amniotic stem cells bank [45][46] was opened in 2009 in Medford, MA, by Biocell Center Corporation[47][48][49] and collaborates with various hospitals and universities all over the world.[50]

Adult stem cells have limitations with their potency; unlike embryonic stem cells (ESCs), they are not able to differentiate into cells from all three germ layers. As such, they are deemed multipotent.

However, reprogramming allows for the creation of pluripotent cells, induced pluripotent stem cells (iPSCs), from adult cells. These are not adult stem cells, but adult cells (e.g. epithelial cells) reprogrammed to give rise to cells with pluripotent capabilities. Using genetic reprogramming with protein transcription factors, pluripotent stem cells with ESC-like capabilities have been derived.[51][52][53] The first demonstration of induced pluripotent stem cells was conducted by Shinya Yamanaka and his colleagues at Kyoto University.[54] They used the transcription factors Oct3/4, Sox2, c-Myc, and Klf4 to reprogram mouse fibroblast cells into pluripotent cells.[51][55] Subsequent work used these factors to induce pluripotency in human fibroblast cells.[56] Junying Yu, James Thomson, and their colleagues at the University of WisconsinMadison used a different set of factors, Oct4, Sox2, Nanog and Lin28, and carried out their experiments using cells from human foreskin.[51][57] However, they were able to replicate Yamanaka’s finding that inducing pluripotency in human cells was possible.

Induced pluripotent stem cells differ from embryonic stem cells. They share many similar properties, such as pluripotency and differentiation potential, the expression of pluripotency genes, epigenetic patterns, embryoid body and teratoma formation, and viable chimera formation,[54][55] but there are many differences within these properties. The chromatin of iPSCs appears to be more “closed” or methylated than that of ESCs.[54][55] Similarly, the gene expression pattern between ESCs and iPSCs, or even iPSCs sourced from different origins.[54] There are thus questions about the “completeness” of reprogramming and the somatic memory of induced pluripotent stem cells. Despite this, inducing adult cells to be pluripotent appears to be viable.

As a result of the success of these experiments, Ian Wilmut, who helped create the first cloned animal Dolly the Sheep, has announced that he will abandon somatic cell nuclear transfer as an avenue of research.[58]

Furthermore, induced pluripotent stem cells provide several therapeutic advantages. Like ESCs, they are pluripotent. They thus have great differentiation potential; theoretically, they could produce any cell within the human body (if reprogramming to pluripotency was “complete”).[54] Moreover, unlike ESCs, they potentially could allow doctors to create a pluripotent stem cell line for each individual patient.[59] Frozen blood samples can be used as a valuable source of induced pluripotent stem cells.[60] Patient specific stem cells allow for the screening for side effects before drug treatment, as well as the reduced risk of transplantation rejection.[59] Despite their current limited use therapeutically, iPSCs hold create potential for future use in medical treatment and research.

To ensure self-renewal, stem cells undergo two types of cell division (see Stem cell division and differentiation diagram). Symmetric division gives rise to two identical daughter cells both endowed with stem cell properties. Asymmetric division, on the other hand, produces only one stem cell and a progenitor cell with limited self-renewal potential. Progenitors can go through several rounds of cell division before terminally differentiating into a mature cell. It is possible that the molecular distinction between symmetric and asymmetric divisions lies in differential segregation of cell membrane proteins (such as receptors) between the daughter cells.[61]

An alternative theory is that stem cells remain undifferentiated due to environmental cues in their particular niche. Stem cells differentiate when they leave that niche or no longer receive those signals. Studies in Drosophila germarium have identified the signals decapentaplegic and adherens junctions that prevent germarium stem cells from differentiating.[62][63]

Stem cell therapy is the use of stem cells to treat or prevent a disease or condition. Bone marrow transplant is a form of stem cell therapy that has been used for many years without controversy.[64][65]

Stem cell treatments may lower symptoms of the disease or condition that is being treated. The lowering of symptoms may allow patients to reduce the drug intake of the disease or condition. Stem cell treatment may also provide knowledge for society to further stem cell understanding and future treatments.[66]

Stem cell treatments may require immunosuppression because of a requirement for radiation before the transplant to remove the person’s previous cells, or because the patient’s immune system may target the stem cells. One approach to avoid the second possibility is to use stem cells from the same patient who is being treated.

Pluripotency in certain stem cells could also make it difficult to obtain a specific cell type. It is also difficult to obtain the exact cell type needed, because not all cells in a population differentiate uniformly. Undifferentiated cells can create tissues other than desired types.[67]

Some stem cells form tumors after transplantation;[68] pluripotency is linked to tumor formation especially in embryonic stem cells, fetal proper stem cells, induced pluripotent stem cells. Fetal proper stem cells form tumors despite multipotency.[69]

Some of the fundamental patents covering human embryonic stem cells are owned by the Wisconsin Alumni Research Foundation (WARF) they are patents 5,843,780, 6,200,806, and 7,029,913 invented by James A. Thomson. WARF does not enforce these patents against academic scientists, but does enforce them against companies.[70]

In 2006, a request for the US Patent and Trademark Office (USPTO) to re-examine the three patents was filed by the Public Patent Foundation on behalf of its client, the non-profit patent-watchdog group Consumer Watchdog (formerly the Foundation for Taxpayer and Consumer Rights).[70] In the re-examination process, which involves several rounds of discussion between the USPTO and the parties, the USPTO initially agreed with Consumer Watchdog and rejected all the claims in all three patents,[71] however in response, WARF amended the claims of all three patents to make them more narrow, and in 2008 the USPTO found the amended claims in all three patents to be patentable. The decision on one of the patents (7,029,913) was appealable, while the decisions on the other two were not.[72][73] Consumer Watchdog appealed the granting of the ‘913 patent to the USPTO’s Board of Patent Appeals and Interferences (BPAI) which granted the appeal, and in 2010 the BPAI decided that the amended claims of the ‘913 patent were not patentable.[74] However, WARF was able to re-open prosecution of the case and did so, amending the claims of the ‘913 patent again to make them more narrow, and in January 2013 the amended claims were allowed.[75]

In July 2013, Consumer Watchdog announced that it would appeal the decision to allow the claims of the ‘913 patent to the US Court of Appeals for the Federal Circuit (CAFC), the federal appeals court that hears patent cases.[76] At a hearing in December 2013, the CAFC raised the question of whether Consumer Watchdog had legal standing to appeal; the case could not proceed until that issue was resolved.[77]

Diseases and conditions where stem cell treatment is being investigated include:

Research is underway to develop various sources for stem cells, and to apply stem cell treatments for neurodegenerative diseases and conditions, diabetes, heart disease, and other conditions.[93] Research is also underway in generating organoids using stem cells, which would allow for further understanding of human development, organogenesis, and modeling of human diseases.[94]

In more recent years, with the ability of scientists to isolate and culture embryonic stem cells, and with scientists’ growing ability to create stem cells using somatic cell nuclear transfer and techniques to create induced pluripotent stem cells, controversy has crept in, both related to abortion politics and to human cloning.

Hepatotoxicity and drug-induced liver injury account for a substantial number of failures of new drugs in development and market withdrawal, highlighting the need for screening assays such as stem cell-derived hepatocyte-like cells, that are capable of detecting toxicity early in the drug development process.[95]

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Stem cell – Wikipedia

Stem Cell Research & Therapy | Home page

“Stem cells have enormous potential for alleviating suffering for many diseases which currently have no effective therapy. The field has progressed to the clinic and it is important that this pathway is underpinned by excellent science and rigorous standards of clinical research. The journal provides an important avenue of publication in translational aspects of stem cell therapy spanning preclinical studies, clinical research and commercialization.”

Timothy O’Brien,Editor-in-Chief,Stem Cell Research & Therapy

“The study of stem cells is one of the most exciting areas of contemporary biomedical research. We believe that Stem Cell Research & Therapy will act as a highly active forum for both basic and translational research into stem cell biology and therapies. Specifically, by developing this forum for cutting edge research, we hope that Stem Cell Research & Therapy will play a significant role in bringing together the critical information to synergize stem cell science with stem cell therapies.”

Rocky S Tuan,Editor-in-Chief,Stem Cell Research & Therapy

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Stem Cell Research & Therapy | Home page

Stem Cells in Milwaukee, WI | Wisconsin Stem Cell Therapy

Dave, age 68, avid hunter and snow skier, his orthopedic surgeon suggested that he would need knee replacement surgery. He instead found relief through our powerful Stem Cell Therapy treatment protocol.

He said about his knee after our treatment, It is 85% better than when I walked in. I would recommend the procedure before trying anything else.

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Stem Cells in Milwaukee, WI | Wisconsin Stem Cell Therapy

NSI Stem Cell | What Is Stem Cell Therapy?

This innovative therapy option for alleviating pain and restoring function in the body could be the answer youve been looking for! We know you may have tried everything, and may have seen numerous doctors to take care of your condition, without real success. This can be very frustrating and can cause a lot of stress on you and your family. It is very important to your recovery to find someone that understands your journey and what you have been through along the way.

You may have been through the ringer with your injury or condition. Many of our patients have spent years getting their hopes up, and then getting their hopes dashed.

Stem Cell Therapy is about using your bodys own stem cells to regenerate damagedtissue. So if you, or someone you love, is suffering please read on to find out who can be helped and how.

Our Stem Cell Therapy is an innovative therapy that is recommendedfor a wide variety of chronic conditions, yet many people are learning about it now for the first time.

These are not embryonic stem cells or cells from fetuses.These regenerative cells come straight from your own body.

They are extracted just a few hours before theyre injected back into your body and put to work to heal damaged or dysfunctional tissue.

We use a variety of stem cells derived from the patients own tissues. Our preferred choice is bone marrow or fat because the cells there are multi-potent which means that they have the ability to differentiate into muscle, tendons, ligaments, bone, and cartilage. Once introduced into the damaged or diseased area, the stem cells can then heal your damaged tissue and regenerate new healthy tissue.

Stem Cell Therapy offers significant potential for the healing of tissues that have become injured as a result of the aging process.

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NSI Stem Cell | What Is Stem Cell Therapy?

Stem Cell Therapy for Osteoarthritis – StemGenex

Stem Cell Therapy for Osteoarthritis

New treatments and advances in research are giving new hope to people affected by Osteoarthritis pain and symptoms. StemGenex provides stem cell therapy for Osteoarthritis to help those with unmet clinical needs achieve optimum health and better quality of life.

Stem cell therapy for Osteoarthritis is being studied for efficacy in improving the complications in patients through the use of their own stem cells. These procedures may help patients who dont respond to typical drug treatment, want to reduce their reliance on medication, or are looking to try stem cell therapy before starting drug treatment.

To learn more about becoming a patient and receiving stem cell therapy for Osteoarthritis through StemGenex, please contact one of our patient advocates at (800) 609-7795 or fill out the contact form on this page.Below are some frequently asked questions about stem cell treatment for Osteoarthritis.

The majority of complications in Osteoarthritis patients are related to the deterioration of cartilage that cushions the ends of bones in your joints. Cartilage is a firm, slippery tissue that permits nearly frictionless joint motion. In Osteoarthritis, this surface become rough. Eventually, if the cartilage wears down completely, patients will be left with bone rubbing on bone.

Stem cell treatment provided by StemGenex is designed to target these areas within the joints to help with the creation of new cartilage cells. Mesenchymal stem cells are multipotent and have the ability to differentiate into cartilage called (chondrytes). The goal of each stem cell treatment is to inject the stem cells into the joint to create cartilage (chondryte cells). Stem cells are a natural anti-inflammatories which can assist with Osteoarthritis pain and swelling in the joint area.

Stem cells are the basic building blocks of human tissue and have the ability to repair, rebuild, and rejuvenate tissues in the body. When a disease or injury strikes, stem cells respond to specific signals and set about to facilitate the healing process by differentiating into specialized cells required for the bodys repair.

There are four known types of stem cells which include:

StemGenex provides autologous adult stem cells (from fat tissue) where the stem cells come from the person receiving treatment.

StemGenex provides autologous adult adipose-derived stem cells (from fat tissue) where the stem cells come from the person receiving treatment.

We tap into our bodys stem cell reserve daily to repair and replace damaged or diseased tissue. When the bodys reserve is limited and as it becomes depleted, the regenerative power of our body decreases and we succumb to disease and injury.

Three sources of stem cells from a patients body are used clinically which include adipose tissue (fat), bone marrow and peripheral blood.

Performed by Board Certified Physicians, dormant stem cells are extracted from the patients adipose tissue (fat) through a minimally invasive mini-liposuction procedure with little to no downtime.

During the liposuction procedure, a small area (typically the abdomen) is numbed with an anesthetic and patients receive mild to moderate sedation. Next, the extracted dormant stem cells are isolated from the fat and activated, and then comfortably infused back into the patient intravenously (IV) and via other directly targeted methods of administration. The out-patient procedure takes approximately four to five hours.

StemGenex provides multiple administration methods for Osteoarthritis patients to best target the disease related conditions and symptoms which include:

Since each condition and patient are unique, there is no guarantee of what results will be achieved or how quickly they may be observed. According to patient feedback, many patients report results in one to three months, however, it may take as long as six to nine months. Individuals interested in stem cell therapy are urged to consult with their physician before choosing investigational autologous adipose-derived stem cell therapy as a treatment option.

In order to determine if you are a good candidate for adult stem cell treatment, you will need to complete a medical history form which will be provided by your StemGenex Patient Advocate. Once you complete and submit your medical history form, our medical team will review your records and determine if you are a qualified candidate for adult stem cell therapy.

StemGenex team members are here to help assist and guide you through the patient process.

Patients travel to StemGenex treatment center located in San Diego, California for stem cell treatment from all over the United States, Canada and around the globe. Treatment will consist of one visit lasting a total of three days. The therapy is minimally invasive and there is little to no down time. Majority of patients fly home the day after treatment.

We provide stem cell therapy for a wide variety of diseases and conditions for which traditional treatment offers less than optimal options. Some conditions include Multiple Sclerosis, Parkinson’s Disease, Rheumatoid Arthritis, Osteoarthritis and Chronic Obstructive Pulmonary Disease (COPD).

The side effects of the mini-liposuction procedure are minimal and may include but are not limited to: minor swelling, bruising and redness at the procedure site, minor fever, headache, or nausea. However, these side effects typically last no longer than 24 hours and are experienced mostly by people with sensitivity to mild anesthesia. No long-term negative side effects or risks have been reported.

The side effects of adipose-derived stem cell therapy are minimal and may include but are not limited to: infection, minor bleeding at the treatment sites and localized pain. However, these side effects typically last no longer than 24 hours. No long-term negative side effects or risks have been reported.

StemGenex provides adult stem cell treatment with mesenchymal stem cells which come from the person receiving treatment. Embryonic stem cells are typically associated with ethical and political controversies.

Stem cell treatment is not FDA approved.

Stem cell for arthritis treatment is not covered by health insurance at this time. The cost for standard preoperative labs are included. Additional specific labs may be requested at the patients expense.

Osteoarthritis, or degenerative joint disease, is the most common type of arthritis. It is caused by the degradation of a joints cartilage. Cartilage is a firm, rubbery material that covers and cushions the ends of bones in normal joints. Its main function is to reduce friction in the joints and serve as an intermediary or cushion.

Over time, the cartilage may wear away in some areas, greatly decreasing its ability to act as a shock absorber. As the cartilage wears away, tendons and ligaments stretch, causing pain. In advanced cases, the bones could rub against each other, causing even more pain and loss of movement.

Osteoarthritis is very common in middle-aged and older people, and its symptoms can range from very mild to very severe. The disorder most often affects hands and weight-bearing joints such as knees, hips, feet and shoulders, but can affect almost any joint in the body.

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Stem Cell Therapy for Osteoarthritis – StemGenex

Stem Cell Therapy | Advanced Regenerative Orthopedics

Stem Cell Therapy involves the use of stem cells to stimulate the bodys natural repair mechanisms to repair, regenerate or replace damaged cells, tissues and organs. This physician-directed therapy is very safe, ethical and does not entail the use of any fetal or embryonic cells or tissue. It has been described as the future of medicine by many prestigious groups including the National Institutes of Health and the Institute of Medicine.

The field of Stem Cell Therapy continues to evolve, focusing on cures rather than just treatments for essentially all types of chronic diseases and conditions, including diabetes and cardiovascular disease, as well as various forms of arthritis and various orthopedic problems. When cells are transplanted into a patient, they do not stay for more than a few days. However, the cells provide a large and robust stimulus to turn on native repair mechanisms. The number of stem cells present in the body and their functional capacity to repair damaged tissue declines with each advancing decade of life, and chronic diseases further impede their ability to respond to chronic injury or damage in the body. This is why research has led to new solutions, which include the use of umbilical cord blood as the source of cells, which have the most potent ability to generate new tissues without risk of rejection. We at Advanced Regenerative Orthopedics use stem cells that are supplied by an FDA-registered cord blood bank.

Stem Cell Therapy and Tissue Engineering are much simpler and effective options that use very powerful young cells to stimulate the patients own native repair mechanisms to regenerate new cartilage and bone. The physician-directed treatment at ARO is a comprehensive approach to a specific joint with the goal of reducing the disabling pain and increasing function.

At Advanced Regenerative Orthopedics, our goal is to provide minimally invasive treatments along with regenerative techniques to target your bodys natural healing ability. Used as part of our innovative, three-tiered approach, physician-directed arthritis stem cell treatment can help patients of all ages get pain relief, increase their joint mobility and enjoy a higher quality of life.

Stem cell therapy can be an effective treatment for those suffering from a broad range of arthritic conditions. By using stem cells for arthritis, Advanced Regenerative Orthopedics stimulates your bodys natural mechanism to repair, regenerate and replace damaged cells within your joints.

If you live in Tampa, Brandon, St. Petersburg, Clearwater, Lakeland, Sarasota, The Villages, Ocala, or the surrounding areas and are interested in learning more about using stem cells for arthritis or any other joint condition, please contact our courteous and efficient office staff today to schedule an appointment. We look forward to discussing the benefits of physician-directed arthritis stem cell treatment with you and determining the best course of treatment to restore your joint health.

As many of our patients travel to us from outside the state of Florida for our world class procedures, our team is very familiar with managing the care & travel for remote patients.

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Stem Cell Therapy | Advanced Regenerative Orthopedics

Stem Cell Therapy for Arthritis

Experts are researching ways to use stem cells to treat arthritis in the knee and other joints. Many doctors already use stem cell therapy to treat arthritis, but it is not considered standard practice.

Stem cell therapy is one of several non-surgical treatments for arthritis pain. See Knee Osteoarthritis Treatment

There is a lot of debate around stem cell treatment, and it is helpful for potential patients to understand what stem cells are and the issues surrounding their use in arthritis therapy.

Article continues below

Stem cells are located throughout the body. What makes stem cells special is that they can:

See What Are Stem Cells?

Advocates of stem cell treatments hypothesize that, when placed into a certain environment, stem cells can transform to accommodate a certain need. For example, stem cells that are placed near damaged cartilage are hypothesized to develop into cartilage tissue.

See What Is Cartilage?

Stem cells can be applied during a surgery (such as the surgical repair of a torn knee meniscus) or delivered through injections directly into the arthritis joint.

Watch: Knee Meniscus Tear Video

When administering stem cell injections, many physicians use medical imaging, such as ultrasound, in order to deliver cells precisely to the site of cartilage damage.

The most common type of stem cells used for treating arthritis are mesenchymal stem cells. Mesenchymal stem cells are usually collected from the patients fat tissue, blood, or bone marrow.

The process of collecting cells is often called harvesting.

Bone marrow is usually taken from the pelvic bone using a needle and syringe, a process called bone marrow aspiration. The patient is given a local anesthetic and may also be given a sedative before the procedure.

There are no professional medical guidelines for who can and cannot receive stem cell therapy for arthritis. For now, the decision about who gets stem cell therapy is up to patients and doctors.

See Arthritis Treatment Specialists

There is some evidence that people with severe arthritis can benefit from stem cell therapy.1 Most research indicates that younger patients who have relatively mild osteoarthritis or cartilage damage see the most benefit.2

See What Is Osteoarthritis?

Some doctors have certain criteria for recommending stem cell therapy. For example, they only recommend it to patients who are healthy and have relatively little cartilage damage. Other doctors make recommendations on a case-by-case basis.

Stem cell therapy is a promising but still unproven treatment, and will not be covered by most insurance companies.

Complete Listing of References

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Stem Cell Therapy for Arthritis


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