Genetically modified organism

A genetically modified organism, or GMO, is an organism whose genetic material has been altered with genetic engineering, by methods that mating or natural recombination could never achieve on their own. Usually a gene that gives a desired trait is identified, copied and inserted into the organism's DNA, although newer genome-editing methods can change existing genes instead. When the added gene comes from another species, the organism is described as transgenic.

The first consumer product of genetic engineering was human insulin made by modified bacteria, approved in the United States in 1982, and the first genetically modified fresh produce, a tomato, went on sale in 1994. Widely grown GM crops include corn, soybeans, cotton, canola and sugar beets. Common traits are insect resistance, often from a gene of the bacterium Bacillus thuringiensis that makes a protein toxic to certain insects, tolerance of herbicides, and resistance to plant viruses. Modified animals and microbes are used to make medicines and in research.

GM foods go through safety assessments for toxicity, allergy risk and nutrition before approval, and those on the market have not been shown to harm human health. Debate continues over environmental effects, such as genes spreading to wild relatives, and over labeling and regulation, which differ between countries.