Status Report on Transgenic Organisms
Crop and Soil Environmental News, December 1997
While previous articles have detailed the commercialization of transgenic (genetically engineered) crops, many questions have been received about development of other types of transgenic organisms such as animals, insects, and fish. This article provides a brief summary of each type of agricultural-oriented genetic engineering research that is being conducted in the U.S. This information was condensed from material provided by USDA, EPA, and the Union of Concerned Scientists.
Animals Engineered for Leaner Meat
Status: No livestock engineered for leaner meat is currently near commercialization. Research done in the 1980s to genetically engineer leaner pigs failed because of unacceptable side effects to the pigs, including low fertility, arthritis, and impaired immune systems. Some low level of research activity in this area is still underway but this area of research is not considered to be a high priority in the livestock industry.
Animals Engineered as Drug-Production Facilities
Status: Goats and sheep have been successfully engineered to secrete bioactive molecules into their blood, urine, or milk. Companies are in the process developing commercial enterprises based on these animals and the compounds that they produce. So far, none of the compounds (drugs for human health) are on the market but the first of these types of drugs should be commercially available within five years. The development of transgenic animals is controversial as it touches on issues such as animal welfare and food safety since the animals may be slaughtered for food after they are no longer useful for drug production.
Animals Engineered as Sources of Transplant Organs
Status: Several companies are engineering pigs so that their organs will not be rejected by human transplant recipients. So far, the organs are not commercially available, but most estimates indicate that such donor animals may be commercially available within ten years. This research includes the same concerns as for drug-production animals regarding animal welfare and food issues about uses of the carcasses of donor pigs.
Animals Engineered for Disease Resistance
Status: Chickens and turkeys have been engineered to be resistant to avian viral diseases. None have been commercialized but commercial development is underway. These will probably be the first transgenic animals to receive commercial approval in the U.S.
Genetically Engineered Fish and Shellfish
Status: Several types of fish and shellfish have been successfully engineered where changes in hormones accelerate growth. The growth hormones successfully engineered into fish include hormones from other fish, from pigs, and from humans. So far, none have been commercialized in the U.S., but transgenic fish should be on the market within five years.
Genetically Engineered Plants Eaten Whole as Food
Status: Many plants have been commercialized, including tomatoes and squash and commodity crops like corn and soybeans. Most have been engineered for one of three traits: herbicide tolerance, insect resistance, or virus tolerance. This is the fastest growing area of biotechnology in agriculture. Other newsletter articles will continue to cover transgenic crops in detail.
Genetically Engineered Fiber Plants
Status: Genetically engineered cotton has been approved for commercial use. There are between 10 and 12 million acres of cotton in the U.S. and estimates are that all of this acreage will be planted to transgenic varieties with the next ten years. One of the newest innovations in cotton is the development of naturally-colored cotton fibers where the pigments have come from inserting the color genes from flowers into cotton.
Engineered Insects Used in Agricultural Systems
Status: No engineered insects have been approved for commercial use. An engineered predatory mite has been field tested in Florida. Researchers have produced honeybees and other beneficial insects engineered to tolerate pesticides. There are no reliable estimates as to when transgenic insects may become commercially available.
Engineered Microorganisms Used as Pesticides
Status: Several bacteria engineered to enhance their ability to kill or repel pests have been approved for commercial use. These products are used as pesticides in agricultural fields and gardens. Other newsletter articles will cover these organisms in detail.
Food Processing Aids Made from Engineered Bacteria
Status: Bacteria have been genetically engineered to produce rennet, an enzyme important in making cheese. Genetically engineered rennet (chymosin) is approved for commercial use and widely used by U.S. cheese processors. Many other commercial enzymes from transgenic bacteria are under development.
Animal and Human Drugs Made by Engineered Plants and Bacteria
Status: Bovine Growth Hormone (BGH) made from engineered bacteria is used commercially to stimulate milk production in cows. Currently this hormone is being used in about 10 percent of the nation's dairy herds. Insulin from transgenic bacteria is commercially available and is used by diabetics who are allergic to the horse serum used in traditional insulin. Many types of transgenic plants are being developed to produce compounds such as drugs for the health care industry. These areas of research are currently receiving a great deal of attention and additional commercial products will continue to appear on the market.