Genetic basis of XX males discovered

Italian team implicates R-spondin1 as an ovary-promoting sex-determination gene

Jeffrey M. Perkel
Oct 15, 2006
A team of Italian researchers has identified a new sex-determination gene, according to a report in Nature Genetics. Genetic analysis has implicated R-spondin1, a member of a relatively new class of mitogens, as an ovary-promoting factor, the loss of which leads to complete sex reversal - that is, to XX males. Despite the notion that female sexual development is a "default" condition, researchers have long known there must be ovary-promoting factors. However, all previous candidates have come up short because they exhibited functional redundancy, according to Robin Lovell-Badge, of the Division of Medical Genetics at MRC National Institute for Medical Research in London.The new study is "a very important piece of work," Lovell-Badge told The Scientist. "I think it will stimulate a lot of activity."Giovanna Camerino, of the University of Pavia in Italy, and colleagues used genetic analysis of a consanguineous Italian family with four XX male...