genetic engineering

All-inclusive term that describes the deliberate manipulation of genetic material by biochemical techniques. It is often achieved by the introduction of new DNA, usually by means of a virus or plasmid. This can be for pure research, gene therapy, or to breed functionally specific plants, animals, or bacteria. These organisms with a foreign gene added are said to be transgenic (see transgenic organism) and the new DNA formed by this process is said to be recombinant. In most current cases the transgenic organism is a micro-organism or a plant, because ethical and safety issues are limiting its use in mammals.

The breakthrough in this field came in 1973, when two biologists at the University of California succeeded in the recombination of two pieces of DNA from organisms that would not reproduce naturally. By the end of the 1970s, scientists were able to add genes to mice to create the first genetically modified (GM) mammal. They also were able to add human genes to bacteria and put this technology to commercial use in manufacturing human proteins for drugs. By early 1995 more than 60 plant species had been genetically engineered, and nearly 3,000 transgenic crops had been field-tested.