A few blogs ago I asked, "Where, in fact, do 'the good ones' really come from?" By "good ones" I meant useful genome changes in evolution. This question stimulated some debate about whether it was possible to distinguish good changes from bad changes before they occur.
In the abstract, this may seem an overwhelmingly difficult problem. But if we think a bit about the highly organized state of the genome and non-random natural genetic engineering, biasing changes toward "good ones" becomes more conceivable.
I have already discussed purposeful, targeted changes in the immune system. The immune system illustrates how efficiently cells can target DNA restructuring by recognizing specific sequences and coupling DNA changes to transcription (copying DNA sequence into RNA).
Some evolutionists object that a somatic process like antibody synthesis provides no model for germline changes in evolution. So let's examine natural genetic engineering events in microbial cells. We'll look at mobile genetic elements targeted in ways that increase their evolutionary potential.
Mobile genetic elements come in many forms. Some operate purely as DNA. Others make an RNA copy and reverse transcribe it back into DNA as it inserts at a new location. Elements that move, or transpose, to multiple new locations are called "transposons" or "retrotransposons" (if they use an RNA intermediate).
Other mobile elements only insert in particular locations by a process called "site-specific" recombination. In bacterial evolution, this process is used in specialized structures called "integrons" that capture casettes containing protein coding sequences for antibiotic resistance, pathogenicity, and other functions.
What all mobile elements share are proteins that aid them to cut and splice DNA chains so that they can construct novel sequences, much as human genetic engineers do in their test tubes. These proteins have various names, such as "recombinase," "transposase," and "integrase." It is the specificity of the cutting reactions involving these proteins that determines where a mobile element moves in the genome.
One fascinating case of highly biased integration is the bacterial transposon Tn7. Tn7 has two specialized proteins to target its transposition. The TnsD protein directs Tn7 to insert into a special "attTn7" site in the chromosomes of many bacterial species where it does not disrupt any host functions and so causes no deleterious effects.
Another, more interesting protein, TnsE, directs Tn7 to insert into replicating DNA molecules. The reason this is important is that transmissible plasmids replicate their DNA as they transfer from one cell to another. TnsE targeting to plasmids in transit to new cells thus enhances the spread of Tn7 and the resistances it carries to many different kinds of bacteria.
Tn7 carries its antibiotic resistance determinants in an integron. Integrons and their recombinase proteins are likewise specialized to participate in plasmid spreading through bacterial populations. Plasmids enter new cells as single-stranded DNA. We learned just in 2005 that integron site-specific recombinases are special in operating on single-stranded DNA, not double-stranded molecules like previously studied recombinases. Moreover, integron recombinase synthesis is triggered by the entrance of single-stranded DNA into a cell. So integron activity is intimately linked in more than one way to plasmid transfer.
Read more:
James A. Shapiro: Can Cells Bias Natural Genetic Engineering Toward Useful Evolutionary Outcomes?
- Who are We? - November 7th, 2009 [November 7th, 2009]
- Vilsack targeted for his Pro-GMOs stand - November 7th, 2009 [November 7th, 2009]
- Call for technology to produce cellulosic ethanol - November 7th, 2009 [November 7th, 2009]
- Kenyan scientists weigh on GMOs - November 7th, 2009 [November 7th, 2009]
- Indian researcher makes a case for biotechnology - November 7th, 2009 [November 7th, 2009]
- Michigan smoothens the way for alternative energy investors - November 7th, 2009 [November 7th, 2009]
- Link of ethanol use to high food prices questioned - November 7th, 2009 [November 7th, 2009]
- EU challenges France on GM Maize - November 7th, 2009 [November 7th, 2009]
- POET rolls out cellulosic ethanol plant - November 7th, 2009 [November 7th, 2009]
- There’s a bright future for cellulosic ethanol investment - November 7th, 2009 [November 7th, 2009]
- Cellulosic ethanol can considerably reduce gasoline use by 2030 - November 7th, 2009 [November 7th, 2009]
- Human Genetic Engineering - Background - November 7th, 2009 [November 7th, 2009]
- Human Genetic Engineering - History - November 7th, 2009 [November 7th, 2009]
- Human Genetic Engineering - Methods - November 7th, 2009 [November 7th, 2009]
- Human Genetic Engineering - Uses - November 7th, 2009 [November 7th, 2009]
- Human Genetic Engineering - Controversy - November 7th, 2009 [November 7th, 2009]
- Human Genetic Engineering - In popular culture - November 7th, 2009 [November 7th, 2009]
- Human genetic engineering - An Introduction - November 7th, 2009 [November 7th, 2009]
- Human Genetic Engineering - A Very Hot Issue! - November 7th, 2009 [November 7th, 2009]
- What are the risks of genetic engineering in humans? (human genetic engineering) - November 7th, 2009 [November 7th, 2009]
- What are the benefits of human genetic engineering? (human genetic engineering) - November 7th, 2009 [November 7th, 2009]
- Genetic Engineering - Ethics and Controversy - November 7th, 2009 [November 7th, 2009]
- Genetic Engineering Ethics In Science Fiction - November 7th, 2009 [November 7th, 2009]
- Genetic Engineering Ethics - November 7th, 2009 [November 7th, 2009]
- Welcome to Pest Control Exterminator Network - December 13th, 2009 [December 13th, 2009]
- OMD - Genetic Engineering - August 27th, 2011 [August 27th, 2011]
- X-Ray Spex - Genetic Engineering - August 27th, 2011 [August 27th, 2011]
- Ancient Alien Nephilim, Giants, Mutants, Genetic Engineering, and Hybrids (2-6) - August 28th, 2011 [August 28th, 2011]
- Human-Plant Hybrid (Genetic Engineering at Home) - August 28th, 2011 [August 28th, 2011]
- Ancient Alien Nephilim, Giants, Mutants, Genetic Engineering, and Hybrids (1-6) - August 29th, 2011 [August 29th, 2011]
- 3. Genetic Engineering - August 29th, 2011 [August 29th, 2011]
- Genetic engineering nightmare - August 31st, 2011 [August 31st, 2011]
- Ancient Alien Nephilim, Giants, Mutants, Genetic Engineering, and Hybrids (3-6) - August 31st, 2011 [August 31st, 2011]
- Future of genetic engineering - by Futurist Dr Patrick Dixon. Genetic mutations and genetic disorders. Gene science by conference keynote speaker - September 2nd, 2011 [September 2nd, 2011]
- Genetic engineering: The world's greatest scam? - September 3rd, 2011 [September 3rd, 2011]
- Watch Fed Up! Genetic Engineering, Industrial Agriculture and Sustainable Alternatives Full Movie Online Part 1/15 - September 3rd, 2011 [September 3rd, 2011]
- Ancient Alien Nephilim, Giants, Mutants, Genetic Engineering, and Hybrids (5-6) - September 5th, 2011 [September 5th, 2011]
- Genetic Engineering, Humans with Animals. - September 6th, 2011 [September 6th, 2011]
- Is Genetic Engineering Good for the Environment? - September 7th, 2011 [September 7th, 2011]
- Open Source Food and Genetic Engineering - Michael Pollan - September 10th, 2011 [September 10th, 2011]
- Ancient Alien ( demons ) Nephilim Giants, Mutants Genetic Engineering and Hybrids.avi - September 11th, 2011 [September 11th, 2011]
- MUST SEE : Genetic Engineering Corn Grows in Sand ! For Those That Appreciate Nature ! - September 12th, 2011 [September 12th, 2011]
- Designing Humanity - Genetic Engineering - September 14th, 2011 [September 14th, 2011]
- Genetic Modification | QUEEN ANNE SCIENCE CAFE - September 14th, 2011 [September 14th, 2011]
- Genetic Engineering in California Agriculture - September 15th, 2011 [September 15th, 2011]
- Genetic Engineering Animation - September 15th, 2011 [September 15th, 2011]
- Proof Of Ancient Genetic Engineering - September 15th, 2011 [September 15th, 2011]
- Joad Cressbeckler Fears Genetic Modification Causes 'Wrath-Minded Taters' - September 16th, 2011 [September 16th, 2011]
- Ethical Concerns With Genetic Engineering - September 16th, 2011 [September 16th, 2011]
- Scientists under Attack - Genetic Engineering in the magnetic Field of Money TRAILER - September 17th, 2011 [September 17th, 2011]
- Genetic Modification - September 18th, 2011 [September 18th, 2011]
- Genetic Engineering Not a New Science - Pamela Ronald - September 23rd, 2011 [September 23rd, 2011]
- The Island of Dr. Moreau prt. IV - September 28th, 2011 [September 28th, 2011]
- Ancient Alien Nephilim, Giants, Mutants, Genetic Engineering, and Hybrids (4-6) - September 30th, 2011 [September 30th, 2011]
- 4. Genetic Engineering (cont.) - October 2nd, 2011 [October 2nd, 2011]
- Ancient Alien Nephilim, Giants, Mutants, Genetic Engineering, and Hybrids (6-6) - October 4th, 2011 [October 4th, 2011]
- Islands at Risk (Part 3) - Genetic Engineering in Hawai'i - October 4th, 2011 [October 4th, 2011]
- Morgellons Is Genetic Engineering , A Silent Superbug - October 4th, 2011 [October 4th, 2011]
- Islands at Risk (Part 2) - Genetic Engineering in Hawai'i - October 4th, 2011 [October 4th, 2011]
- The Ethics of Genetically Engineering Children - Arthur Caplan - October 4th, 2011 [October 4th, 2011]
- Disney Geneticists Debut New Child Stars - October 4th, 2011 [October 4th, 2011]
- Genetic Engineering and Society, Lecture 1a, Honors Collegium 70A, UCLA - October 4th, 2011 [October 4th, 2011]
- OMD - Genetic Engineering (312mm Version) (Audio Only) - October 4th, 2011 [October 4th, 2011]
- The difference between normal and genetically modified food - October 4th, 2011 [October 4th, 2011]
- Bioethics Of Human Genetic Engineering - Documentary Video - October 6th, 2011 [October 6th, 2011]
- Islands at Risk (Part 1) - Genetic Engineering in Hawai'i - October 6th, 2011 [October 6th, 2011]
- Coast To Coast AM: Genetic Engineering 3-24-2011 Download Link - October 6th, 2011 [October 6th, 2011]
- Lloyd Pye - Ancient Genetic Engineering - October 13th, 2011 [October 13th, 2011]
- X RAY SPEX - ROUNDHOUSE LONDON GENETIC ENGINEERING - Video - October 13th, 2011 [October 13th, 2011]
- OMD - Genetic Engineering 1983 - Video - October 14th, 2011 [October 14th, 2011]
- OMD - GENETIC ENGINEERING - Video - October 14th, 2011 [October 14th, 2011]
- Mechanism of Recombination - Video - October 15th, 2011 [October 15th, 2011]
- Harvard Prof. Michael Sandel on Human Genetic Modification, Berkeley, CA, 7 May 2007 - Video - October 15th, 2011 [October 15th, 2011]
- Genetic Engineering [Medical Ethics Series] - (excerpt) - Video - October 15th, 2011 [October 15th, 2011]
- Genetic Engineering and Society, Lecture 1b, Honors Collegium 70A, UCLA - Video - October 24th, 2011 [October 24th, 2011]
- Genomics: genetic modification (genetic engineering) and the human gene project - Video - October 26th, 2011 [October 26th, 2011]
- Genetically Engineering Intelligent Babies - Horizon: Are We Still Evolving? Preview - BBC Two - Video - October 27th, 2011 [October 27th, 2011]
- "GENETIC ENGINEERING" GERMAN REGIME feat THIRSTIN HOWL THE3RD - Video - October 28th, 2011 [October 28th, 2011]
- Science 360: Genetic Engineering - Video - October 31st, 2011 [October 31st, 2011]
- UFOTV Presents... - Bad Seed: Danger of Genetically Modified Food - Video - November 8th, 2011 [November 8th, 2011]