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Опубликованно: 27.12.2005.
Язык: Английский
Уровень: Университет
Литературный список: Нет
Ссылки: Не использованы
Фрагмент работы

What is Genetic Engineering?
Genes are the fundamental chemical codes that determine the physical nature of all living things, from the tiniest single-celled organism to human beings. Genes make up DNA, the cell-level master plan which determines how the organism is going to develop in all ways that are not environmentally influenced.
Genetic engineering is sometimes also called bioengineering or biotechnology (biotech for short). All these terms refer to making artificial changes in the genes of the DNA of a living thing. Its nature and characteristics are then changed, often in ways that could never occur naturally. Some of the effects of genetic engineering are known, but most are not. The effects we may have information about are all short term, specific and physical. The effects that remain unknown are long term, general, and mental.
Genetic engineering of foods involves the insertion of genes from plants, bacteria, insects, fish, animals or humans into the DNA of another plant, fish, or animal to create a new variety. In the case of plants this is usually done either to enhance herbicide resistance, reduce susceptibility to cold or frost damage, or increase rates of growth. Human growth genes have been introduced into food plants, fish and animals to enhance growth rates.
Differences between Genetic Engineering and Breeding
In the breeding of animals and plants, the natural processes of gene selection and mutation that occur in nature are manipulated to develop new varieties that have specific use for humans. In selecting those varieties, breeders both modify the processes of natural selection and are restricted by them. For example, the well-known breeding work of Luther Burbank led to the introduction of many tasty new fruits, but not even Burbank could cross a fruit with an animal. Unlike breeding, the new varieties created by genetic engineering often are the result of crossing species barriers and so could never occur in nature.
When Is It Coming?
Because almost all genetically engineered foods are not labeled, most people are not aware that they are probably already consuming them. Most cheeses contain genetically engineered rennet; milk may contain rBGH, a genetically engineered growth hormone; genetically engineered tomatoes and squashes are already on the market. In addition, the next few months should see an explosion in the numbers of genetically engineered products on supermarket shelves. Monsanto Corporation is flooding the soybean market with soybeans genetically engineered to resist large applications of the herbicide Roundup. Soybeans are found not only in tofu but also in about 60% of all processed foods. Genetically engineered corn and canola are also being widely grown in this country. Scores of new genetically engineered food plants are already in production, and genetically engineered meat and fish will be probably be sold soon.
Potential Health Dangers
So much money is at stake that international corporations which have invested heavily in biotechnology have exerted heavy political pressure on the FDA and USDA, the government agencies responsible for regulating genetic engineering. They have been successful in getting them to decrease their regulation of genetic engineering and to ban required labeling of genetically engineered foods based on scientific claims about problems with it. The FDA now asserts that genetically engineered foods are essentially no different in their nutritional value and health risks from non-genetically engineered foods. Many prominent scientists disagree. There has been no long term testing of their effects. Scientific studies have already shown that in some cases serious allergic reactions can occur, and that antibiotic resistance and toxicity levels may be increased.
Environmental Problems
The main environmental problem with genetically engineered food plants and animals is that, when they escape into the wild, they permanently disrupt ecosystems which are the products of billions of years of evolution (or, if you prefer, of God's perfect creation). For example, the most recent conservative scientific estimates indicate that genetically engineered plants will probably cross-pollinate with wild relatives, thereby escaping into the wild and permanently disrupting ecosystems at about one percent a year. That means they will probably cause major environmental problems in about ten years.
Another potential problem area is viruses. By their very nature, viruses invade the genetic material of their hosts and often break apart and recombine using part of the host's genetic material to create new viruses. When this happens with genetically engineered plants and animals outside of the laboratory, new viruses will be created that incorporate genetically engineered genetic material. The viruses will then spread and, because they could not have been naturally produced, there may be no natural defenses against them. Depending upon the kind of virus, they may then cause widespread death of certain plants or animals, or even of humans.
Ethical Problems

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