Genetic engineering (GE), also called genetic modification, is a branch of applied biology. It is the changing of an organism's genome using biotechnology. These methods are recent discoveries. The techniques are advanced, and full details are not given here.

This is an overview of what can be done:

• new DNA may be inserted in the host genome by getting a DNA sequence, and then putting this into the host organism by using a molecular biology vector.
• genes may be removed, or "knocked out", using an enzyme called a zinc finger nuclease.
• gene targeting is a different technique which uses recombination to change a gene. It can be used to delete a gene, remove exons, add a gene, or introduce mutations.

An organism that is altered by genetic engineering is a genetically modified organism (GMO). The first GMOs were bacteria in 1973; GM mice were made in 1974. Insulin-producing bacteria were commercialized in 1982. Genetically modified food has been sold since 1994, including crops.

Stanley Cohen

Herbert Boyer

Herbert Boyer and Stanley Cohen created the first genetically modified organism in 1973