metafemale

A metafemale (or superfemale) is a low viability Drosophila fruit fly with a female phenotype in which the ratio of X chromosomes to sets of autosomes (A) exceeds 1.0.{{cite book|last1=King|first1=Robert C.|last2=Mulligan|first2=Pamela Khipple|last3=Stansfield|first3=William D.|year=2013|title=A dictionary of genetics|edition=8th

|location=Oxford|publisher=Oxford University Press|isbn=978-0-19-976643-7|pages=189, 288, 458}}

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.). For example: a fly with one X chromosome and two sets of autosomes is a normal male, a fly with two X chromosomes and two sets of autosomes is a normal female, and a fly with three X chromosomes and two sets of autosomes (or four X chromosomes and three sets of autosomes) is a metafemale.

American geneticist Calvin Bridges, who discovered the genic balance sex-determination system in Drosophila in 1921, used the terms "superfemale" and "supermale".{{cite journal|last=Bridges|first=Calvin B.|date=September 16, 1921|title=Triploid intersexes in Drosophila melanogaster|journal=Science|volume=54|issue=1394|pages=252–254|doi=10.1126/science.54.1394.252|pmid=17769897|jstor=1646022|url=http://mcb.berkeley.edu/courses/mcb240/Cline%20MCB240%20Fall%2006%20Assigned%20papers/Lecture%201,%20Jan%2020/Bridges%201921.pdf}} German-American geneticist Curt Stern proposed the alternative terms "metafemale" and "metamale" in 1959.{{cite journal|last=Stern|first=Curt|date=December 12, 1959|title=Use of the term 'superfemale'|journal=Lancet|volume=274|issue=7111|page=1088|doi=10.1016/S0140-6736(59)91557-0}}