The human Y chromosome is not likely to disappear

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PUBLIC RELEASE DATE:

9-Jan-2014

Contact: Melissa A. Wilson Sayres mwilsonsayres@berkeley.edu Public Library of Science

Is the male Y chromosome at risk of being lost? Recent work by Dr Wilson Sayres and colleagues at UC Berkeley, published in PLOS Genetics, demonstrates that the genes on the Y chromosome are important: they have probably been maintained by selection. This implies that despite its dwindling size, the Y chromosome will be sticking around.

The human Y chromosome contains 27 unique genes, compared to thousands on other chromosomes. Some mammals have already lost their Y chromosome (despite still having males, females and normal reproduction); this has led some researchers to speculate that the Y chromosome is superfluous.

As the X and Y chromosomes evolved, male-specific genes became fixed on the Y chromosome. Some of these genes were detrimental to females, so the X and Y chromosomes stopped swapping genes. This meant the Y chromosome was no longer able to correct mistakes efficiently and has thus degraded over time.

There is low genetic diversity in the human Y chromosome, and Dr Wilson Sayres and colleagues were able to precisely measure this by comparing variation on a person's Y chromosome with variation on that person's other 22 chromosomes, the X chromosome and the mitochondrial DNA. The researchers then showed that this low genetic diversity cannot be explained solely by a reduction in the number of males passing on their Y chromosome (successfully fathering male offspring). Instead, the low diversity must also result from natural selection, in this case purifying selection (the selective removal of deleterious alleles).

The movements of human populations around the world are tracked by variations in the Y chromosome. The increased understanding provided by this research will improve estimates of humans' evolutionary history.

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The human Y chromosome is not likely to disappear

Why is type 2 diabetes an increasing problem?

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PUBLIC RELEASE DATE:

9-Jan-2014

Contact: Aileen Sheehy press.office@sanger.ac.uk 44-012-234-92368 Wellcome Trust Sanger Institute

Contrary to a common belief, researchers have shown that genetic regions associated with increased risk of type 2 diabetes were unlikely to have been beneficial to people at stages through human evolution.

Type 2 diabetes is responsible for more than three million deaths each year and this number is increasing steadily. The harmful genetic variants associated with this common disease have not yet been eliminated by natural selection.

To try to explain why this is, geneticists have previously hypothesised that during times of 'feast or famine' throughout human evolution, people who had advantageous or 'thrifty' genes processed food more efficiently. But in the modern developed world with too much food, these same people would be more susceptible to type 2 diabetes.

"This thrifty gene theory is an attractive hypothesis to explain why natural selection hasn't protected us against these harmful variants," says Dr. Yali Xue, lead author of the study from the Wellcome Trust Sanger Institute. "But we find little or no evidence to corroborate this theory."

The team tested this theory by examining 65 genetic regions that were known to increase type 2 diabetes risk, the most detailed study of its kind.

If these harmful variants were beneficial in the past, the team would expect to see a genetic imprint of this in the DNA around the affected regions. Despite major developments in tests for positive selection and a four-fold increase in the number of genetic variants associated with diabetes to work with, they found no such imprint.

"We found evidence for positive selection in only few of the 65 variants and selection favoured the protective and risk alleles for type 2 diabetes in similar proportions," notes Dr. Qasim Ayub, first author from The Wellcome Trust Sanger Institute, "This is no more than what we would expect to find for a random set of genomic variants."

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Why is type 2 diabetes an increasing problem?

Health care sign up improves, but some states seek workarounds for tech issues

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JUDY WOODRUFF: It's been just over a week since some Americans first started getting health insurance coverage through the new marketplaces.

The federal website and the government's enrollment efforts seem to be working substantially better, but there are still a fair share of questions and complications, including for some people eligible for Medicaid going online at HealthCare.gov. And there have been troubles for some of the state-created exchanges.

Sarah Kliff is following all this for The Washington Post.

And it's good to you have back with us.

SARAH KLIFF, The Washington Post: Thank you.

JUDY WOODRUFF: So, Sarah, let's stipulate that things, as we said, do seem to be generally going better for the sign-up process. That's your understanding?

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SARAH KLIFF: Yes.

JUDY WOODRUFF: But let's talk about, for example, people who are eligible for Medicaid, going on the federal Web site and some of them are having problems. Tell us about that.

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Health care sign up improves, but some states seek workarounds for tech issues

USC TREET Seminar Series: Eric Hoffman – Molecular and Clinical Outcome Measures in Rehab Medicine – Video

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USC TREET Seminar Series: Eric Hoffman - Molecular and Clinical Outcome Measures in Rehab Medicine
Eric Hoffman, PhD presents "Molecular and Clinical Outcome Measures in Rehabilitation Medicine: The National Center for Medical Rehabilitation Research in Wa...

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Genetic testing to produce more offspring

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Jan. 9, 2014 The Fleckvieh is a breed of cattle that originated in the Alpine region. A robust animal, it is now found on every continent, with an estimated worldwide population of around 40 million.

In Germany, there are approximately 1 million Fleckvieh dairy cows: "Their genomes can be traced back to a small number of key ancestors," explains Prof. Ruedi Fries, Chair of Animal Breeding at TUM. "With artificial insemination, male breeding animals can produce more than one hundred thousand offspring."

Infertility caused by a single gene

This practice is fraught with risk, however: If the genetic make-up of any animal contains an unidentified defect, this characteristic will be passed on to future generations. TUM researchers have now discovered that a mutation in the TMEM95 gene on cattle chromosome 19 makes bulls effectively infertile, with a success rate for insemination of less than 2 percent.

"Otherwise, the animals are perfectly healthy and normal," points out Dr. Hubert Pausch, lead author of the study. "The characteristic only manifests itself if bulls inherit the mutation from both the male and female side, i.e. they are homozygous for the defective gene. It is only in this case that the animals should be excluded from breeding." Routine genetic testing for all breeding bulls has been underway since August 2012.

Findings of interest for human medicine

As part of their study, the researchers compared the genome of 40 subfertile animals with 8,000 breeding bulls with normal fertility levels. They discovered that the genetic defect can be traced back to one Fleckvieh animal born in 1966.

The TMEM95 gene encodes a protein on the surface of the sperm heads. The protein probably mediates the binding process between the sperm and egg cells. If it is missing, fertilization will not occur.

"Our findings indicate that genetic defects in TMEM95 could also cause infertility in men," elaborates Pausch. During their investigation of the sperm of infertile breeding bulls, the TUM scientists collaborated with Prof. Sabine Klle and Dr. Matthias Trottmann from Munich's Ludwig Maximilian University. Trottmann helps couples with infertility problems.

Genetic analysis for healthier animals

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Genetic testing to produce more offspring

Lions Face Extinction in West Africa

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Fewer than 250 adults may be left in West Africa, and those big cats are confined to less than 1 percent of their historic range.

The new study, detailed in the journal PLOS ONE, suggests that without dramatic conservation efforts, three of the four West African lion populations could become extinct in the next five years, with further declines in the one remaining population, study co-author Philipp Henschel, the lion program survey coordinator for Panthera, a global wildcat conservation organization, wrote in an email. [In Photos: The Biggest Lions on Earth]

The majestic lion once roamed throughout West Africa, from Nigeria to Senegal.

But as people have converted wild lands to pastureland, hunted the lion's traditional prey antelopes, gazelles, wildebeest, buffalos and zebras and gotten into conflicts with the animals, the big cat population has plummeted in West Africa.

Cash-strapped West African governments have put little money into lion conservation, in part because "wildlife tourism is quasi-absent in West Africa," Henschel said.

And research institutions have similarly neglected the region.

"Like wildlife tourists, most international research institutions and conservation organizations active in Africa also flock to the iconic game parks in East and southern Africa, meaning that lions faced a silent demise in West Africa over the past decades," Henschel told LiveScience.

Massive Survey

To remedy that, Henschel and his colleagues recently completed a massive, six-year survey of West Africa's lions, using remote cameras, interviews with people and counts of lion tracks. The survey, carried out between October 2006 and May 2012, builds on a smaller study done last year, which found shrinking savannas for lions in the region.

About 400 adult and juvenile lions existed in the region. And the wild cats, which were originally thought to have inhabited 21 separate regions, actually exist in just four. Their range is now confined to pockets in Senegal, Nigeria and the borderlands between Benin, Niger and Burkina Faso.

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Gene Therapy – Answers.com – Answers – The Most Trusted Place …

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One of the main problems with gene therapy is that there is a very low possibility that the plasmid with the new piece of DNA will be correctly inserted into the DNA in the human DNA for several reasons: a) The host cell (bacteria, virus or liposome which has been more recently used) has difficulties in travelling successfully to the human cell in the specific organ or tissue. (e.g.: lungs) If the host cell is a virus, the body can easily destroy them because as the virus touches the surface of the membrane, antibodies will attack it as the cell membrane has glycocalyx which are carbohydrates that can recognize molecules or cells that are not common in the body.

b) It is also because the new piece of DNA has to enter the DNA strand in the correct place. Usually, in a part where the bases are not coding for any protein.

Another negative effect might be that when the new piece of DNA enters the human DNA strand, it can have a terrorific effect on it. This happens when it successfully enters the DNA strand but it replaces or simply disrupts the sequence of amino acids which code for an important protein. (This has occured in the 1980s with the X-SCID disease)

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Gene therapy for Parkinson’s produces promising results in first patient trial

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The ProSavin treatment uses an inert virus to carry corrective genes directly into the striatum region of the brain that controls movement.

It is designed to convert ordinary nerve cells into factories for making dopamine, the signalling chemical that is lost in Parkinson's patients.

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Lack of dopamine activity leads to the common Parkinson's symptoms of tremor, slow movement and rigidity.

The trial tested the safety, tolerability and effectiveness of three different doses of ProSavin in 15 patients aged 48 to 65 with advanced Parkinson's disease who were not responding to conventional treatments.

A standard system of rating motor functions was used, covering speech, tremors, rigidity, finger taps, posture, gait, and slow movement. Lower scores indicated better muscle control and co-ordination.

Significant score improvements were seen after six months and a year in all patients not taking medication.

Reporting their findings in The Lancet medical journal, the researchers led by Professor Stephane Palfi, from Les Hopitaux Universitaires Henri-Mondor in Creteil, France, wrote: "ProSavin was safe and well tolerated in patients with advanced Parkinson's disease. Improvement in motor behaviour was observed in all patients."

They stressed that, while promising, the results at this stage were still limited and should be "interpreted with caution".

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Gene therapy for Parkinson's produces promising results in first patient trial

Gene therapy provides hope for Parkinson’s sufferers

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10/01/2014 - 07:15:45Back to World Home

A gene therapy for Parkinsons disease has produced promising results in its first patient trial, say researchers.

The ProSavin treatment uses an inert virus to carry corrective genes directly into the striatum region of the brain that controls movement.

It is designed to convert ordinary nerve cells into factories for making dopamine, the signalling chemical that is lost in Parkinsons patients.

Lack of dopamine activity leads to the common Parkinsons symptoms of tremor, slow movement and rigidity.

The trial tested the safety, tolerability and effectiveness of three different doses of ProSavin in 15 patients aged 48 to 65 with advanced Parkinsons disease who were not responding to conventional treatments.

A standard system of rating motor functions was used, covering speech, tremors, rigidity, finger taps, posture, gait, and slow movement. Lower scores indicated better muscle control and co-ordination.

Significant score improvements were seen after six months and a year in all patients not taking medication.

Reporting their findings in The Lancet medical journal, the researchers led by Professor Stephane Palfi, from Les Hopitaux Universitaires Henri-Mondor in Creteil, France, wrote: ProSavin was safe and well tolerated in patients with advanced Parkinsons disease. Improvement in motor behaviour was observed in all patients.

They stressed that, while promising, the results at this stage were still limited and should be interpreted with caution.

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Gene therapy provides hope for Parkinson's sufferers

Novel gene therapy for Parkinson’s clears hurdle

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PARIS: A closely-watched prototype therapy to inject corrective genes into the brain to treat Parkinson's disease has cleared an important safety hurdle, doctors said Friday.

Tested on 15 volunteers with an advanced form of the degenerative nerve disease, the technique proved safe and the results were encouraging, they said.

The experiment aims to reverse the lack of a brain chemical called dopamine, which is essential for motor skills.

It entails tucking three genes into a disabled horse virus of the family lentiviruses.

The modified virus is then injected directly into a specialised area of the brain, where it infiltrates cells. In doing so, it delivers corrective pieces of DNA, prompting defective brain cells to once again start producing dopamine.

Called ProSavin, the British-designed treatment was authorised for tests on humans after it was tried on lab monkeys.

It is being closely watched by specialists to see if it works better than conventional therapies -- the veteran drug levodopa or electrical stimulation of the brain -- or another experimental gene technique which uses a modified cold virus.

French neurosurgeon Stephane Palfi, who led the early-stage trial published in The Lancet, said 15 patients aged 48-65 were given the genes in one of three doses.

They developed better coordination and balance, had less muscle twitching and improved speech.

Assessed at least 12 months after the injection, "motor symptoms remained improved in all the patients," Palfi said.

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Novel gene therapy for Parkinson's clears hurdle

Nicholas Webb – Futurist, Speaks on Innovation, Customer Service – Video

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Nicholas Webb - Futurist, Speaks on Innovation, Customer Service
Nicholas J. Webb is a world-renowned business futurist and innovation thought leader. Webb is the author of The Innovation Playbook and The Digital Innovation Playbook. He is also a successful...

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