Genetic engineering is a set of technologies used to change the genetic makeup of cells, including thetransfer of genes within and across species boundaries to produce improved or novel organisms. The techniques involve sophisticated manipulations of genetic material and other biologically important chemicals.

Genes are the chemical blueprints that determine an organism's traits. Moving genes from one organism to another transfers those traits. Through genetic engineering, organisms can be given targeted combinations of new genesand therefore new combinations of traitsthat do not occur in nature and, indeed, cannot be developed by natural means. Such an approach is different from classical plant and animal breeding, which operates through selection across many generations for traits of interest. Classical breeding operates on traits, only indirectly selecting genes, whereas biotechnology targets genes, attempting to influence traits. The potential of biotechnology is to rapidly accelerate the rate of progress and efficiency of breeding.

Novel organisms

Nature can produce organisms with new gene combinations through sexual reproduction. A brown cow bred to a yellow cow may produce a calf of a completely new color. But reproductive mechanisms limit the number of new combinations. Cows must breed with other cows (or very near relatives). A breeder who wants a purple cow would be able to breed toward one only if the necessary purple genes were available somewhere in a cow or a near relative to cows. A genetic engineer has no such restriction. If purple genes are available anywhere in naturein a sea urchin or an iristhose genes could be used in attempts to produce purple cows. This unprecedented ability to shuffle genes means that genetic engineers can concoct gene combinations that would never be found in nature.

New risks

Genetic engineering is therefore qualitatively different from existing breeding technologies. It is a set of technologies for altering the traits of living organisms by inserting genetic material that has been manipulated to extract it from its source and successfully insert it in functioning order in target organisms. Because of this, genetic engineering may one day lead to the routine addition of novel genes that have been wholly synthesized in the laboratory.

In addition to desired benefits, novel organisms may bring novel risks as well. These risks must be carefully assessed to make sure that all effectsboth desired and unintendedare benign. UCS advocates caution, examination of alternatives, and careful, contextual, case-by-case evaluation of genetic enginering applications within an overall framework that moves agricultural systems of food production toward sustainability.

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What Is Genetic Engineering? | Union of Concerned Scientists