A metamale (or supermale) is a low viability Drosophila fruit fly with a male phenotype in which the ratio of X chromosomes to sets of autosomes (A) is less than 0.5. For example: a fly with one X chromosome and two sets of autosomes is a normal male, a fly with one X chromosome and three sets of autosomes is a metamale.
American geneticist Calvin Bridges, who discovered the genic balance sex-determination system in Drosophila in 1921, used the terms "superfemale" and "supermale". German-American geneticist Curt Stern proposed the alternate terms "metafemale" and "metamale" in 1959.
- King, Robert C.; Mulligan, Pamela Khipple; Stansfield, William D. (2013). A dictionary of genetics (8th ed.). Oxford: Oxford University Press. pp. 189, 288, 458. ISBN 978-0-19-976643-7.
genic balance: a mechanism of sex determination, originally discovered in Drosophila, that depends on the ratio of X chromosomes to sets of autosomes (A). Males develop when the X/A ratio is 0.5 or less, females develop when the X/A ratio is 1.0 or greater, an intersex develops when the ratio is between 0.5 and 1.0. See Appendix C, 1925, Bridges; metafemales, metamales, sex determination.
metafemale: in Drosophila, a female phenotype of relatively low viability in which the ratio of X chromosomes to sets of autosomes exceeds 1.0, previously called a superfemale. See intersex, metamale.
metamale: in Drosophila, a poorly viabile male characterized by cells containing one X and three sets of autosomes, previously called a supermale. See intersex, metafemale.
superfemale: metafemale (q.v.).
supermale: metamale (q.v.).
- Bridges, Calvin B. (September 16, 1921). "Triploid intersexes in Drosophila melanogaster". Science 54 (1394): 252–254. doi:10.1126/science.54.1394.252. JSTOR 1646022. PMID 17769897.
- Stern, Curt (December 12, 1959). "Use of the term 'superfemale'". Lancet 274 (7111): 1088. doi:10.1016/S0140-6736(59)91557-0.