Genetic Signature Of Female Promiscuity

Sexual selection is defined as the competition for mates between individuals of the same sex, and was proposed by Darwin to be a powerful force driving evolution. Postcopulatory sperm competition is a well-studied example of sexual selection, and has been shown to affect the evolution of traits associated with reproductive physiology, such as testis size and sperm count (the greater the number of potential competitors, the larger the number of sperm it is desirable to have). Semen coagulum, a component of the seminal fluid, has also been shown to be critical in preventing fertilization of a recently inseminated female by other males. Lahn and co-workers show that SEMG2 is evolving fastest in primate species in which females are the most sexually promiscuous (chimpanzees and macaques). Humans fall in the middle of the range, but are difficult to assess given the cultural influences on mating behavior. Presumably, the rapidly evolving versions of SEMG2 in chimpanzees are being selected for effectiveness in preventing fertilization by competing sperm, although this has not yet been demonstrated directly.

Author contact:
Bruce T. Lahn (University of Chicago, Chicago, IL, USA)
Tel: +1 773 834 4393, E-mail: blahn@bsd.uchicago.edu

Also available online.

(C) Nature Genetics press release.

Message posted by: Trevor M. D'Souza