Transgenic means that one or more DNA sequences from another species has been introduced by artificial means. For example, animals usually are made transgenic by having a small sequence of DNA injected into a fertilized egg or developing embryo. Transgenic plants can be made by introducing foreign DNA into a variety of different tissues.
Most transgenic organisms are generated in the laboratory for research purposes. Others have been developed for commercial purposes such as golden rice that has been modified to produce beta-carotene, the precursor to vitamin A.