Genetic modification (GM) is the alteration of a living organism's genetic make-up by transferring one or more genes from one organism to another. These modifications are then passed on to the organism's descendants. This is also known as genetic engineering, gene splicing or recombinant DNA technology. An organism whose genes have been altered this way is called "genetically modified".
GMO stands for Genetically Modified Organism, referring to organisms which have been modified by the new methods of genetic engineering.
The most common types of genetic modification of crops at the moment are altering them to be resistant to herbicides and altering them to be more tolerant to biotic stresses (pests and diseases) and abiotic stresses (drought, low temperature, salinity). The reason behind these modifications is to be able to grow stronger crops that need fewer herbicides and other pesticides which would benefit the environment. The problem with modifying plants to be resistant to herbicides is that this will also cause the weeds to become increasingly resistant to these herbicides. This defeats the whole purpose of the genetic engineering and will actually result in a need to use either more herbicides or to switch to more toxic chemicals, causing an increased pollution of soil and ground water.
Another advantage biotech companies mention is the possibility of genetic engineering to get larger yields from crops which can help solve our global nutritional situation. Global hunger however, will not be fixed by genetic engineering. Even though our crop production has tripled since the 1950s, more people go hungry now than 20 years ago. Social, political, economic and environmental problems are responsible for hunger. Argentina for instance is the second largest producer of genetically modified crops in the world. These crops however are exported for cattle feed while millions of Argentineans go hungry.
Genetic modification is also used to alter other traits of an organism, like its nutritional properties, shelf-life, flavor or processing characteristics. For rice it has been used to create a product called "Golden Rice", which contains beta carotene and iron. For tomatoes it has been used to alter the protein that breaks down the cell walls of the tomato, creating firmer ripe tomatoes called Flavr Savr tomatoes. For cheese it was used to create cheese that is suitable for vegetarians, using the fermentation-produced enzyme chymosin instead of extracting it from the stomachs of slaughtered calves. In March 1990, Chymosin was the first genetically modified derived food ingredient for which the Food and Drug Administration (FDA) issued a regulation in the U.S., affirming that it is "generally recognized as safe" (GRAS). A product that has received the GRAS status by the FDA is exempt from the premarket approval requirements that apply to new food additives.
Gene flow is the exchange of genes between species. Most of the worlds major crops naturally hybridize with wild relatives. A crop that has been genetically engineered to be herbicide-tolerant for instance could transfer these new genes to their wild relatives making them also more herbicide-tolerant. What makes the problem even worse is the fact that genetically-engineered crops are even more likely to interbreed with other plants than regular crops. All genetically-engineered organisms include genes that are designed to overcome natural reproductive barriers between organisms. These genes make it possible to transfer genes over from another organism. A study by Dr. Joy Bergelson of the University of Illinois was published in the September 3rd, 1998 edition of the Journal Nature. The study showed that genetically engineered mustard plants were 20 times more likely to crossbreed than regular mustard plants growing right next to them. The negative consequence of this gene flow could be the loss of unique varieties.
Gene flow also causes a so-called "genetic contamination" of non-genetically engineered crops. This is a special concern for organic farmers. More organic farmers are reporting traces of genetically modified organisms in their crops. Even though organic products are allowed to contain trace amounts of genetically engineered material, organic farmers don't want to lose the faith of their customers who expect the gene flow to be controlled. Gene flow also effects conventional growers who want to export their products to countries that won't allow genetic engineering, like European countries and Japan. Rice farmers in California are afraid they will lose their Japanese customers if their crops are contaminated by genetically engineered organisms. In March 2004 genetically engineered corn was found in Mexico despite a six-year-old biotechnology ban in that country. In Hawaii, organic papaya farmers are finding traces of genetically engineered papaya in their harvest. In Oregon, genetically engineered grass had hybridized with conventionally grown grass 12 miles away.
There are still many questions about the safety of consuming genetically modified foods. The exposure of humans to large amounts of novel proteins that have never been in the human food chain could cause unpredictable problems. One concern with genetically modified organisms is the risk for allergic reactions. Problems with allergenicity are difficult to detect, because symptoms can take a long time to develop. To limit these risks, the FDA requires scientific evidence for each genetically modified organism showing that they have not incorporated an allergenic substance into it. In case this can't be proven, the FDA requires the a label on the genetically modified organism to warn the consumer of possible allergic reactions. These regulations however do not protect the consumer from unexpected effects as a result of the newly introduced genetic material, including the possibility of new allergens.
Proponents of genetic modification argue that it is not fundamentally different from breeding or cultivation. The difference however is that genetic modification, unlike the other methods, creates unnatural recombinations. Genetic modification recombines the genetic material of species for which there is no, or very low, probability of natural offspring. New genes or DNA sequences are introduced into unpredictable chromosomal locations within the cell DNA of the recipient, which can result in unpredictable effects on the metabolism, physiology and biochemistry of this recipient.
Documented Possible Problems
Genetic engineering can cause unpredictable effects. Effects on the environment and human health cannot be reliably predicted and genetically engineered organisms should therefore not be released into the environment or the food chain.
Pioneer abandoned their plans to genetically modify soybeans with a gene from the Brazil nut on order to enhance the nutritional content of the soybeans. These genetically modified soybeans were intended to be used to feed chickens. Pioneer cancelled their program after studies showed that the Brazil nut gene transferred a potential for allergenicity to the soybeans.
There are many concerns regarding genetically engineered bovine growth hormone (BGH), which is injected into cows in order to increase their milk production. Research has shown that milk from BGH treated cows may cause an increased risk of mammary cancer.
Tobacco plants were genetically engineered to produce gamma-linolenic acid. However, the plants mainly produce the toxic product actadecatetraenic acid. Unmodified tobacco plants don't produce this toxic substance.
Yeast was genetically modified to obtain increased fermentation. An unexpected side effect was an accumulation of the metabolite methyl-glyoxal in toxic and mutagenic concentrations.
One possible problem with genetically modified maize occurred at the beginning of 2004. A large number of people living in a village close to a genetically modified maize field on the island of Mindanao in the Philippines suffered from fevers, respiratory illnesses and skin reactions. The maize, called Bt maize, contains a pesticide in the gene. The health problems started in the autumn of 2003 when the crop was producing pollen. Doctors first thought that the problems were caused by an infectious disease, which was disproved when four families left the village and recovered, but showed the same symptoms on return. After studying the case, the scientists concluded that the Bt maize might have caused the ailments. Blood tests showed that the villagers had developed antibodies to the Bt maize's inbuilt pesticide. The findings by the scientists were immediately challenged by Monsanto, the world's leading GM company, and by the Philippine government. Monsanto argues that there are "no documented cases of allergic reactions to Bt maize after seven years of broad commercial use on millions of hectares in the U.S., Canada, Argentina, Spain and South Africa". Greenpeace called for more research, because "there is such a huge uncertainty around these crops".
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Copyright © 2004 by Wanda Embar. All Rights