An organism that contains one or more artificially inserted genes, typically from another species. Transgenesis provides the potential for an organism to express a trait that it normally would not.

For Example:

This image (to the right) (courtesy of R. L. Brinster and R. E. Hammer) shows a transgenic mouse (right) with a normal littermate (left). The giant mouse developed from a fertilized egg transformed with a recombinant DNA molecule containing:

  • the gene for human growth hormone
  • a strong mouse gene promoter

The levels of growth hormone in the serum of some of the transgenic mice were several hundred times higher than in control mice. [Kimball's Biology Pages]