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Genetic modification is the manipulation of an organism's genes to introduce particular traits. All methods of breeding modify the genes, but the technique that is usually implied by the term "genetic modification," and that attracts the greatest deal of controversy, is DNA recombination - introducing genes from one species into another.
 Tools of the trade
There are several methods to obtain organisms with more favourable genetic make-up. All of these occur in nature to some degree; even DNA recombination can happen naturally, through viruses. All important modern crops have been extensively modified by human action.
- Selective breeding is the oldest method, dating back to the beginnings of agriculture, and uses the same fundamental mechanism as natural evolution. The primary difference is that,
menpeople select for desired traits in individuals, rather than the natural events determining survival and reproductive opportunity (natural selection. Most commercially important plants and animals are a result of centuries of this process; cows were bred from the now-extinct aurochs, chickens from the red jungle fowl, and pigs from wild boars.
- Hybridisation involves crossing two highly dissimilar strains of an organism with each other. Because most detrimental alleles are recessive, and are unlikely to occur in both strains, this results in organisms that suffer from very few genetic defects (sometimes called "heterosis" or "hybrid vigour"). Examples include the sunflower and "broccoflower" (broccoli x cauliflower) for plants, and the mule (mare and jackass) for animals. Hybrids are sometimes sterile, specially within the animal kingdom.
- Doubled haploidy involves the action of the chemical colchicine, which interferes with reduction division and causes gametes to contain two sets of chromosomes rather than one. This results in an organism in which all traits are homozygous. This crude modification can lead to a number of important effects, such as making a plant fertile after wide crossing.
- Mutation breeding involves subjecting organisms (usually plants) to chemical mutagens or ionising radiation. This increases the rate of mutation, and therefore the chance of finding new interesting traits (also the chance of fucking up everything and killing the plant, but who's counting?). Over 2500 registered varieties have been obtained through radiation breeding.
- DNA recombination, the most recent of the bunch, is basically genetic copy-paste; the genetic code of an organism is directly modified by inserting foreign genes into its DNA, often through a specially prepared virus or bacterial plasmid. This is the most precise and powerful method of genetic manipulation, and also the only one that attracts substantial controversy. Examples of this are E. coli strains with genes to make insulin.
Genetic modification has a wide range of applications. The most common genetically modified crops are designed to resist pests, herbicides, and changes in the environment; have an increased yield; have additional nutrients not found in "wild" foods; and/or stay fresh for longer periods after harvesting.
Other uses of genetic modification range from the production of insulin to the creation of a new lithium-ion battery to glow-in-the-dark monkeys, up to creating superheroes or, if otherwise inclined, your very own Legion of TerrorDo You Believe That?.
 Controversy over GM food
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Genetic modification plays straight into what Isaac Asimov called "The Frankenstein Complex," where there is an irrational fear of those who "play God" by mucking with nature. Indeed, many opponents refer to GM food as "Frankenfood".
In a somewhat more rational manner, GM food opponents argue that global food shortages could be overcome by other methods such as better distribution and that genetic modification is done only to line the pockets of companies such as Monsanto. Monsanto sells seed for various GM crops developed to resist their (now out of patent) wide-spectrum herbicide glyphosate (RoundUp®); weeding is accomplished, then, by spraying growing fields with glyphosate. Of course, weeds are now developing resistance to ever-increasing levels of glyphosate.
Several concerns have been raised over GM foods:
- Concern over lack of "independent testing" of GM foods. Non-GM varieties are not tested at all, so even manufacturer testing is a substantial improvement.
- The rise in food allergies correlating to the rise of GM foods. All that can be said is correlation does not equal causation. The rise in allergies is a common phenomenon in developed countries, even though the popularity of GM food varies wildly between them.
- The impact on the environment where GM resistance leads to increased use of pesticides and herbicides. So far the evidence is mixed: some GM crops increase pesticide use, while other decrease it dramatically. In most cases where pesticide use increases, there is a shift to less toxic pesticides, so the environmental impact is nonetheless positive. The effect is also dependent on farming practices in the given area.
- What might happen if modified genes transfer laterally to other organisms. For example, herbicide resistance could transfer to related weedy species, producing herbicide resistant weeds - obviously an undesirable outcome. Occurrence of this gene flow has been confirmed in field studies, but so far it's uncertain whether this is a serious concern or not. It should be noted that herbicide and pesticide resistance is not a concern unique to GM crops.
- The legal implications of cross-pollination between GM crops and non-GM crops planted on other farms nearby. When a Canadian farmer selected for GM traits in canola pollinated from a neighboring field (by spraying his own field with glyphosate), and then used the seed on his farm, Monsanto successfully sued him for patent infringement.
- A common myth perpetrated by GM opponents is that the crops use "terminator seed" technology (technical name Genetic Use Restriction Technology, GURT) which causes the crops to yield sterile seeds. Firstly, while testing has been conducted on GURT, there is actually a moratorium on its commercial use due to public opposition. Secondly, despite all the propaganda, GURT is actually a good thing, because it rules out the transfer of GM traits to weeds - one of the realistic concerns about GM crops - without introducing any new problems. Seed that cannot be saved for replanting is nothing new. Plants grown from traditional hybrid seed, in wide use since the 1920s, do not produce true copies in the second generation. Therefore, new seed must be bought every year from a plant breeder to keep its desirable characteristics.
So far, all evidence is overwhelmingly in favor of safety of GM foods for human consumption. Some even argue that the anti-scientific repression of GM foods by the environmental movement is the real problem. At least one high-profile environmentalist has changed his anti-GMO stance as a result of learning the actual science. (Did he simply sell out to Monsanto? Every anti-GMO blogger at the time thought so, but evidence has not been forthcoming.) The environmental issues are more worthy of concern, in particular the possibility of herbicide-resistant GM crops to transfer the herbicide resistance trait into related wild or weedy species.
 The Seralini study
In 2012, an anti-GMO crank named Gilles-Eric Seralini published a study purporting to document that rats fed GMO corn got more cancer than those not fed it. It has been thoroughly debunked, by, among others, many letters to the editor of the journal in which it was published, Orac of Respectful Insolence,, and a blogger named Tom Worstall at Forbes. Seralini failed to provide data on the amount of food he fed the rats and their growth rates.
As soon as the study got publicized, seeing that GMO food might be banned because of it, the French academies of Agriculture, Medicine, Pharmacy, Science, Technology, and Veterinary Science all went into damage control mode, condemning it as a "scientific non-event."
 Human genetic engineering
The prospect of human genetic engineering has also been extremely controversial, less for health reasons and more out of ethical concerns. The practice does not now exist, but prenatal screening now allows parents to test a fetus or zygote for gender or disease. Critics point to a slippery slope, arguing that if parents can choose to only bear male children or rule out any children with a heightened risk of cancer, then it's likely that when technology allows they will also choose to bear only exceptionally intelligent children or those with other commonly-desired traits, such as blue eyes.
Movies such as the 1997 science fiction thriller Gattaca have conceived of a world rigidly stratified by genetic code, where the wealthy bear superhumans and a person's opportunities for advancement - as well as the concurrent creativity and growth of society - is limited to what's dictated by their genes. Surprisingly, this raises a good question that is as yet unanswered: does the diversity brought about by genetic variation and flaws outweigh the personal costs of parents' private tragedy?
 See also
- National Research Council's 2004 statement on the safety of genetically engineered foods.
- Scientific Facts on Genetically Modified Crops, Green Facts
- Tomorrow's Table
- ↑ Edible Geography: Strange and Beautiful Seeds From the Atom
- ↑ Like frost-resistant strawberries.
- ↑ Like golden rice, which adds beta-carotene to normal rice to combat Vitamin A deficiencies in impoverished countries.
- ↑ Like the "Flavr-Savr" [sic] tomato.
- ↑ http://www.npr.org/templates/story/story.php?storyId=102647672
- ↑ http://blogs.discovermagazine.com/80beats/2009/05/27/green-glowing-monkeys-are-called-a-genetic-engineering-milestone/
- ↑ http://www.innerself.com/Health/frankenfood.htm
- ↑ I'm a Starry-Eyed Techno-Utopian, PZ Myers
- ↑ http://www.mindfully.org/Pesticide/More-GMOs-Less-Pesticide.htm
- ↑ Watrud, L.S. et al., Evidence for landscape-level, pollen-mediated gene flow from genetically modified creeping bentgrass with CP4 EPSPS as a marker. Proceedings of the National Academy of Sciences, October 5, 2004, vol. 101, no. 40, pp. 14533-14538.
- ↑ Monsanto Canada Inc. v. Schmeiser
- ↑ Federal Court (Canada) decision - Monsanto Canada Inc. v. Schmeiser
- ↑ GURT overview.
- ↑ http://aggie-horticulture.tamu.edu/archives/parsons/vegetables/seed.html
- ↑ Peer Reviewed Publications on the Safety of GM Foods
- ↑ Prospect Magazine: The real GM food scandal
- ↑ Leading Environmental Activist’s Blunt Confession: I Was Completely Wrong To Oppose GMOs, Slate.com, 3-Jan-2013
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- ↑ Gattaca, Internet Movie Database