Encyclopedia > Genetically modified organism
Genetically modified organism
For instance, a bell pepper may have DNA from a fish added to it to make it more frost-tolerant.
Both the terms GE (Genetically Engineered) and GMO (Genetically Modified Organism) are commonly used to refer to all organisms that have added genes from another species which were inserted through the techniques of genetic engineering. Less frequently heard terms include GMP (Genetically Modified Plant), GMA (Genetically Modified Animal), or phrases such as "Genetically Damaged Food", "Genetically Diseased Food Substitutes", or "Frankenfood".
Genetic modification is the subject of controversy in its own right - some believe that the science itself should be forbidden.
Genetic modification within agriculture is an issue of some strong debate in the United States, the European Union, and some other countries.
Proponents of genetic modification argue that it allows great advances in agriculture (for instance, making plants more tolerant of certain diseases or of water shortages, increasing their nutrient value, or decreasing their cost of production), as well as allowing other beneficial creations such as the petroleum-eating bacteria. Opponents generally argue that the ultimate results of releasing genetically modified organisms are not predictable and may have unexpected and irreversible effects on the environment; since genetically modified organisms, like conventional organisms, are patentable under some laws (such as the U.S. law), GMO crops can theoretically harm agriculture itself, by leaving independent farmers unable to purchase seed each year. (see biopiracy).
These concerns have varying impact, depending on particular national circumstances. Some argue that the patent issue is not necessary valid in developed nations as some hybrid crops seeds (already eligible for patents) are likely to be purchased anyway (e.g. corn).
Proponents typically dismiss published concerns as bad science and alarmism. They state that genetic modification offers enormous benefits in terms of improved agricultural efficiency and the resulting beneficial health effects of better nutrition. Opponents typically point to the many unstudied issues and warn that mistaken assumptions about safety could result in disaster. This controversy is many years from being resolved. (see precautionary principle).
The practice of genetic modification, as a scientific technique, is unrestricted in the United States; individual GMO crops are subject to intense study before being brought to market and are common in the United States and estimates of their market saturation vary widely. Many countries in Europe have taken the opposite position: that genetic modification has not been proven safe, and therefore that they will not accept genetically modified food from the United States or any other country. This issue has already gone before the World Trade Organization, which determined that not allowing GMO food into the country created an unnecessary obstacle to international trade.
It is almost certainly true that not all genetic modifications have the same effects on health or on the environment; those policies that classify all genetic modifications as good or bad are thus overgeneralized. However, indefinite postponement of policy decisions may not be in the public interest.
Besides, those arguing for application of the precautionary principle insist one of the risk of using GMO is the one of seeing natural species being contaminated by GMO (for example, natural canola aquiring the new GMO canola genes through cross-pollination). They fear natural non transformed species could be led to disappear (due to the genetic selective advantage of the transformed species), resulting in loss of biodiversity.
The standard agricultural practice of applying certain (but not all) pesticides to crop plants has been shown (cite the research) to result in short- and long-term harmful effects in humans. There is therefore some question as to whether genetically-modified crops that confer pest resistance might be harmful to humans as well. Current pest-resistant strains use a relatively innocuous toxic protein derived from the bacterium Bacillus thuringiensis (Bt). However, harmfulness is an area of great controversy not only among the general public, but among scientists as well.
Research conducted by scientists at Imperial College London[?] and the Universidad Simon Rodrigues[?] in Caracas, Venezuela recently revealed that the diamondback moth[?] grew 56% faster when fed cabbage genetically modified to contain Bt than it did when fed cabbage without the Bt. Scientists speculate that the moth is metabolizing the Bt and using it as an additional food source.
Evidence for environmental impact
There is already some strong evidence that the cultivation of a genetically modified plant may lead to environmental changes. However, whether a genetically modified plant can itself harm the environment is a matter of controversy among scientists.
For example, the overproduction of insecticide in a transgenic population induces a heavier selective pressure on insects, hence leading to further resistance to the insecticide in the insect population and reducing the effect of this pesticide when applied to non-GMO crops. In Australia, the Agriculture department noticed that the parasite of cotton plant, supposed to be killed by the GMO cotton Ingard was proliferating [1] (http://www.abc.net.au/rural/news/stories/s279777.htm).
Another impact is noticed upon the use of GM plants resistant to herbicides. For example, the use of Round-up has tripled in 3 years with the increasing area cultivated with GM-roundup-resistant soybeans. Glyphosate[?], commonly known as Roundup, is the world's most widely used herbicide (112,000 tonnes of glyphosate was used world-wide in 1998). 71% of genetically engineered crops planted in 1998 are designed to be resistant to herbicides such as glyphosate. The United States Department of Agriculture (USDA) statistics from 1997 show that the use of Roundup Ready soybeans resulted in a 72% increase in the use of glyphosate. Roundup is a total herbicide, whose toxicity has several times been questioned, not so much because of its active agent (glyphosate) but for the inactive ingredients, such as the surfactant agent polyoxy-ethyleneamine (POEA)]] [2] (http://www.pan-uk.org/pestnews/actives/glyphosa.htm). These components are responsible for acute toxicity to humans such as eye irritation. Ingestion of Roundup has been proven to cause diarrhea in very high exposures. Some studies have also reported Glyphosate could be involved in some non-Hodgkin's lymphoma [3] (http://www.biotech-info.net/glyphosate_cancer). In California, Roundup has been identified as the third most commonly reported cause of pesticide-related illness amongst farmers exposed to bulk quantities, generally as eye irritation (Cox, 1995 b, Pease et al.1993). Glyphosate residues have been found in strawberries (Cessna & Cain, 1992), lettuce, carrots, barley (U.S. EPA, 1993), and fish (Wang et al., 1994, Folmar et al., 1979). Glyphosate residues persisted a long time after the glyphosate was used (for example, lettuce, carrots, and barley contained glyphosate residues at harvest when planted a year after treatment (U.S. EPA, 1993). Glyphosate was also reported killing fish at concentrations as as low as 10 parts per million (WHO, UNEP & ILO, 1994).
References:
- http://www.biotech-info.net/pusztai_article reviews a number of toxicologic studies and concludes that there were design and/or model flaws in most.
- http://www.aces.uiuc.edu/~asap/expanded/gmo/sci_main describes more of the controversy, also citing studies.
References
Pease W S et al. (1993) Preventing pesticide-related illness in California agriculture: Strategies and priorities. Environmental Health Policy Program Report. Berkeley, CA: University of California. School of Public Health. California Policy Seminar.
Wang Y, Jaw C and Chen Y (1994) Accumulation of 2,4-D and glyphosate in fish and water hyacinth. Water Air Soil Pollute. 74:397-403
Recent evidence shows that genetically-modified plants may "escape" from fields in which they were planted and out-compete unmodified plants in surrounding fields.
References:
- BBC News article http://news.bbc.co.uk/1/hi/sci/tech/753586.stm by environment correspondent Alex Kirby. Discusses possible pollen escape in the U.K. and includes links to other articles on the same topic.
- Allison Snow, an Ohio State University professor who received Scientific Americans first annual Research Leader in Agriculture award, has reported (http://www.osu.edu/researchnews/archive/sungene.htm) on several studies showing the strengthening of weeds due to genetic escape of the Bt variant.
- Independent article on the study showing that diamondback moths grow faster on cabbage engineered to contain Bt than they do on cabbage without it. http://news.independent.co.uk/uk/environment/story.jsp?story=392044
See Also
environmentalism, gene therapy, pesticide, bt corn, protein engineering
external links
http://www.gene.ch/genet/1999/Jun/msg00012
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