Rate of molecular evolution of the seminal protein gene SEMG2 correlates with levels of female promiscuity.
Postcopulatory sperm competition is a key aspect of sexual selection and is believed to drive the rapid evolution of both reproductive physiology and reproduction-related genes. It is well-established that mating behavior determines the intensity of sperm competition, with polyandry (i.e., female promiscuity) leading to fiercer sperm competition than monandry. Studies in mammals, particularly primates, showed that, owing to greater sperm competition, polyandrous taxa generally have physiological traits that make them better adapted for fertilization than monandrous species, including bigger testes, larger seminal vesicles, higher sperm counts, richer mitochondrial loading in sperm and more prominent semen coagulation. Here, we show that the degree of polyandry can also impact the dynamics of molecular evolution. Specifically, we show that the evolution of SEMG2, the gene encoding semenogelin II, a main structural component of semen coagulum, is accelerated in polyandrous primates relative to monandrous primates. Our study showcases the intimate relationship between sexual selection and the molecular evolution of reproductive genes.
Dorus
Steve
S
Howard Hughes Medical Institute, Department of Human Genetics, University of Chicago, Chicago, Illinois 60637, USA.
Evans
Patrick D
PD
Wyckoff
Gerald J
GJ
Choi
Sun Shim
SS
Lahn
Bruce T
BT
D000818:Animals; D001483:Base Sequence; D019143:Evolution, Molecular; D006801:Humans; D016013:Likelihood Functions; D016014:Linear Models; D008957:Models, Genetic; D008969:Molecular Sequence Data; D011323:Primates / Q000235:genetics* / Q000502:physiology*; D012641:Selection, Genetic; D029607:Seminal Vesicle Secretory Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012726:Sexual Behavior, Animal / Q000502:physiology*
D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen