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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