Many biological processes of the fruit fly are similar to those in higher organisms, including the mouse and humans. Drosophila homeotic genes seem to function in much the same way in the mouse; thus they probably act similarly in humans. Homologous genes from many other Drosophila regulatory genes have been identified in mammals. Many oncogenes are related to genes that play important roles during the development of Drosophila. These similarities have and will continue to shed light on many medical problems that face our society.