A fruit fly, used extensively in research, mainly because they are well understood, have a short 2 week life cycle, they are easy to handle, cheap and easy to keep in large numbers.

There are two major projects going on in sequencing the fruit fly (Drosophila melanogaster) genome: the European Drosophila Genome Project (EDGP) and the Berkeley Drosophila Genome Project (BDGP). The fruit fly genome was sequenced by BDGP in version 1.0 by 24th of March 2000 in cooperation with Celera Genomics.

These fruit flies are also used to study hox (homeobox) genes, the genes which control which parts of the body go where. This study is what has given rise to the theme commonly used in rubbishy sf movies (and an episode of the X-Files) of having giant drosphila with lots of big chopping arms. Instead, hox genes are manipulated to give the flies things like legs in place of antennae, or vice versa.