Drosophila is a genus of small flies (family Drosophilidae), commonly called fruit flies, which contains about 1,500 known species. The best known of these is Drosophila melanogaster which has been used extensively in laboratory studies of genetics. D. melanogaster has the advantages of being easily bred, has a short generation time, and can be easily obtained in mutant form. It was used by Thomas Hunt Morgan in his pioneering work that established the relationship between genes and chromosomes.