Genetic Engineering

The DNA contained in genes determines inherited characteristics. Modifying DNA to remove, add, or alter genetic information is called genetic modification or genetic engineering. In the early 1980s, scientists developed recombinant DNA techniques that allowed them to extract DNA from one species and insert it into another. Refinements in these techniques have allowed identification of specific genes within DNA—and the transfer of that particular gene sequence of DNA into another species. For example, the genes responsible for producing insulin in humans have been isolated and inserted into bacteria. The insulin that is then produced by these bacteria, which is identical to human insulin, is then isolated and given to people who have diabetes. Similarly, the genes that produce chymosin, an enzyme that is involved in cheese manufacturing, have also been inserted into bacteria. Now, instead of having to extract chymosin from the stomachs of cows, it is made by bacteria. This type of application of genetic engineering has not been very controversial. However, applications involving the use of plants have been more controversial.

Among the first commercial applications of genetically engineered foods was a tomato in which the gene that produces the enzyme responsible for softening was turned off. The tomato could then be allowed to ripen on the vine without getting too soft to be packed and shipped. As of 2002, over forty food crops had been modified using recombinant DNA technology, including pesticide-resistant soybeans, virus-resistant squash, frost-resistant strawberries, corn and potatoes containing a natural pesticide, and rice containing beta-carotene. Consumer negativity toward biotechnology is increasing, not only in the United States, but also in the United Kingdom, Japan, Germany, and France, despite increased consumer knowledge of biotechnology. The principle objections to biotechnology and foods produced using genetic modification are: concern about possible harm to human health (such as allergic responses to a "foreign gene"), possible negative impact to the environment, a general unease about the "unnatural" status of biotechnology, and religious concerns about modification.

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