Commonly called the “fruit fly,” this species is a model organism for the study of specific genes in multicellular development and behavior. Its haploid genome contains about 176 million nucleotide pairs. Of these, about 110 million base pairs are unique sequences, present in the euchromatin (q.v.). The diagram below shows the relative lengths of the sex chromosomes (X and Y), the major autosomes (2 and 3), and the microchromosome (4) as they appear at the metaphase stage of mitosis. The numbers give the amounts of DNA in megabases for the adjacent segments. About 13,000 genes are located in the euchromatin, and about 20% of these have been defined chemically. The average gene contains four exons, and the average transcript is made up of 3,060 nucleotides. Many Drosophila genes show base sequence similarities to human genes. For example, comparative studies of 290 human genes that increase susceptibility to cancer showed that 60% have Drosophila orthologs (q.v.). See Classification, Arthropoda, Insecta, Diptera; Chronology, 1910, 1911, 1912, 1919, Morgan; 1913, 1925, 1926, Sturtevant; 1917, 1919, 1921, 1923, 1925, 1935, Bridges; 1916, 1918, 1927, Muller; 1933, Painter; 1935, Beadle and Ephrussi; 1966, Ritossa et al.; 1972, Pardue et al.; 1973, Garcia-Bellido et al.; 1974, Tissiers et al.; 1975, McKenzie et al.; 1978, Lewis; 1980, Nüsslein-Volhard and Wieschaus; 1982, Bingham et al., Spradling and Rubin; 1983, Scott et al., Bender et al.; 1984, Bargiello and Young; 1987, Nüsslein-Volhard et al.; 1988, MacDonald and Struhl; 1990, Milicki et al.; 1993, Maroni; 1994, Tully et al., Orr and Sohal; 1995, Halder et al., Zhao, Hart, and Laemmli, Kerrebrock et al.; 1996, Dubnau and Struhl, Rivera-Pomar et al.; 1998, Lim, Serounde, and Benzer; 2000, Adams et al., Rubin et al.; centromere, Drosophila targeted gene expression technique, heterochromatin, shotgun sequencing.
The genome sequence of Drosophila melanogaster. Reprinted with permission from M. D. Adams et al., 2000, Science 287 (5461): 2185–2195. © 2000 American Association for the Advancement of Science.
Subjects: Genetics and Genomics.