Genetic engineering (GE) is the modification of an organism's genetic composition by artificial means, often involving the transfer of specific traits, or genes, from one organism into a plant or animal of an entirely different species. When gene transfer occurs, the resulting organism is called transgenic or a GMO (genetically modified organism).
Genetic engineering is different from traditional cross breeding, where genes can only be exchanged between closely related species. With genetic engineering, genes from completely different species can be inserted into one another. For example, scientists in Taiwan have successfully inserted jellyfish genes into pigs in order to make them glow in the dark. 1
All life is made up of one or more cells. Each cell contains a nucleus, and inside each nucleus are strings of molecules called DNA (deoxyribonucleic acid). Each strand of DNA is divided into small sections called genes. These genes contain a unique set of instructions that determine how the organism grows, develops, looks, and lives.
During genetic engineering processes, specific genes are removed from one organism and inserted into another plant or animal, thus transferring specific traits.
Nearly 400 million acres of farmland worldwide are now used to grow GE crops such as cotton, corn, soybeans and rice. 2 In the United States, GE soybeans, corn and cotton make up 93%, 88% and 94% of the total acreage of the respective crops. 3 The majority of genetically engineered crops grown today are engineered to be resistant to pesticides and/or herbicides so that they can withstand being sprayed with weed killer while the rest of the plants in the field die.
GE proponents claim genetically engineered crops use fewer pesticides than non-GE crops, when in reality GE plants can require even more chemicals. 4 This is because weeds become resistant to pesticides, leading farmers to spray even more on their crops. 4 This pollutes the environment, exposes food to higher levels of toxins, and creates greater safety concerns for farmers and farm workers.
Some GE crops are actually classified as pesticides. For instance, the New Leaf potato, which has since been taken off grocery shelves, was genetically engineered to produce the Bt (Bacillus thuringiensis) toxin in order to kill any pests that attempted to eat it. The actual potato was designated as a pesticide and was therefore regulated by the Environmental Protection Agency (EPA), instead of the Food & Drug Administration (FDA), which regulates food. Because of this, safety testing for these potatoes was not as rigorous as with food, since the EPA regulations had never anticipated that people would intentionally consume pesticides as food. 5
Adequate research has not yet been carried out to identify the effects of eating animals that have been fed genetically engineered grain, nor have sufficient studies been conducted on the effects of directly consuming genetically engineered crops like corn and soy. Yet despite our lack of knowledge, GE crops are widely used throughout the world as both human and animal food.
Scientists are currently working on ways to genetically engineer farm animals. Atlantic salmon have been engineered to grow to market size twice as fast as wild salmon, 6 chickens have been engineered so that they cannot spread H5N1 avian flu to other birds, 7 and research is being conducted to create cattle that cannot develop the infectious prions that can cause bovine spongiform encephalopathy (aka mad cow disease). 8 At this point, no GE animals have been approved by the FDA to enter the food supply. 9 Genetic engineering experiments on animals do, however, pose potential risks to food safety and the environment.
In 2003, scientists at the University of Illinois were conducting an experiment that involved inserting cow genes into female pigs in order to increase their milk production. They also inserted a synthetic gene to make milk digestion easier for the piglets. Although the experimental pigs were supposed to be destroyed, as instructed by the FDA, 386 offspring of the experimental pigs were sold to slaughterhouses, where they were processed and sent to grocery stores as pork chops, sausage, and bacon. 10
University of Illinois representatives claimed that the piglets did not inherit the genetic modifications made to their mothers, but there was still a clear risk to the people who purchased products made from the 386 piglets. Since no genetically engineered animal products have ever been approved by the FDA, the pork products that reached supermarket shelves were technically illegal for human consumption. As a result of the accident, the FDA sent letters in May 2003 to all land-grant universities, reminding researchers that their work "may require" licensing under the animal drug law. 10
Many concerns have been raised over the inadequate testing of the effects of genetic engineering on humans and the environment. Genetic engineering is still an emerging field, and scientists do not know exactly what can result from putting the DNA of one species into another. The introduction of foreign DNA into an organism could trigger other DNA in the plant or animal to mutate and change. 11 In addition, researchers do not know if there are any long-term or unintended side effects from eating GE foods. 12
Critics of genetic engineering believe that GE foods must be proven safe before they are sold to the public. Specific concerns over genetic engineering include: 11
Once released into the environment, genetically engineered organisms cannot be cleaned up or recalled. So, unlike chemical and nuclear contamination, which can at least be contained, genetic pollution cannot be isolated and separated from the environment in which it is spreading.
GE crops can cross-pollinate related weed species, passing on their ability to survive the application of weed killers. Even without passing on that specific genetic trait, the widespread adoption of GE crops that are resistant to herbicides like Roundup has led to dramatic increases in the use of this weed killer, and weeds have gradually developed resistance to the herbicide. This leads to the evolution of superweeds that are very difficult to control. Already, superweeds have infested 12 million acres in the United States. 13 At least 20 weed species worldwide are resistant to Roundup, including aggressive weeds like ragweed, pigweed and waterhemp. 14
Some GE seeds are engineered so that plants cannot reproduce their seeds. In many parts of the world, saving seeds from season to season is the only way farmers are able to survive and continue growing food. However, with GE technology, seeds can be sterile, forcing farmers to rely on seed companies for their livelihood, an expense they may not be able to bear.
* These GE crops were approved by the federal government, but are not known to be commercially available. 16