A metafemale (or superfemale) is a low viability ''

Drosophila ''Drosophila'' (), from Ancient Greek δρόσος (''drósos''), meaning "dew", and φίλος (''phílos''), meaning "loving", is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or p ...

'' fruit fly with a female

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

in which the ratio of X chromosomes to sets of

autosome An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosomes ...

s (A) exceeds 1.0.
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 Calvin Blackman Bridges (January 11, 1889 – December 27, 1938) was an American scientist known for his contributions to the field of genetics. Along with Alfred Sturtevant and H.J. Muller, Bridges was part of Thomas Hunt Morgan's famous "Fly R ...

, who discovered the genic balance

sex-determination system A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most organisms that create their offspring using sexual reproduction have two common sexes, males and females, and in ...

in ''Drosophila'' in 1921, used the terms "superfemale" and " supermale". German-American geneticist

Curt Stern Curt Stern (August 30, 1902 – October 23, 1981) was a German-born American geneticist. Life Curt Jacob Stern was born into a middle-class Jewish family in Hamburg, Germany on August 30, 1902. He was the first son of Earned S. Stern, born ...

proposed the alternative terms "metafemale" and " metamale" in 1959.

References

External links

* ** Chromosomal Sex Determination in Mammals
/span>. Bethesda, Md.:

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...

. ** Chromosomal Sex Determination in Drosophila
/span>. Bethesda, Md.:

. Drosophilidae Insect reproduction {{Drosophilidae-stub