Describing an organism whose genome incorporates and expresses genes from an unrelated organism, particularly one of another species. Transgenic individuals are created by genetic engineering, using suitable vectors to insert the desired foreign gene into the fertilized egg or early embryo of the host. For example, the gene for rat growth hormone can be inserted into fertilized mouse eggs to produce mice with cells that produce rat growth hormone. Transgenic organisms offer considerable commercial potential; see genetically modified organisms (Feature). Compare genome editing.