A 14 year behavioral and genetic study of a population of wild capuchin monkeys has shown that fathers almost never mate with their daughters, even though alpha males sire the majority of offspring produced by females unrelated to them. The findings suggest that psychological or other sophisticated behavioral barriers have evolved in this primate species to prevent inbreeding within individual populations.
It has long been known that in group-living mammals, almost all members of at least one sex leave their birth group at adolescence, hindering inbreeding by separating opposite-sexed adult kin. In species in which the same male breeds in a group for a sufficiently long period that he risks mating with his daughters, females are typically the dispersing sex. Capuchins are highly unusual in that long male-breeding tenures co-exist with lifelong female residence in the same group.
In the new work, funded by the Max Planck Institute for Evolutionary Anthropology, geneticists Laura Muniz and Linda Vigilant teamed up with capuchin-monkey researchers Susan Perry, Joseph Manson, Hannah Gilkenson, and Julie Gros-Louis to examine patterns of paternity during the reigns of three male capuchins whose tenures at alpha rank ranged from 7 to 13 years. The three males sired 79% of infants born to females other than their daughters, but only 6% (1 of 17) of infants produced by their daughters. These findings suggest the existence of evolved psychological barriers to father-daughter inbreeding in capuchins. Other potential explanations of these results, such as a general male mating preference for older females, were ruled out by the data. Because courtship and copulations involving fertile females are rarely observed in this species, it will require further research to determine whether it is the behavior of males, females, or both sexes that prevents inbreeding in capuchins.
The findings are reported in the March 7th issue of Current Biology.
The researchers include Laura Muniz, Hannah Gilkenson, and Linda Vigilant of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany; Susan Perry and Joseph H. Manson of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany and UCLA, Los Angeles, CA; Julie Gros-Louis of Indiana University in Bloomington, Indiana.
Muniz et al.: "Father–daughter inbreeding avoidance in a wild primate population." Publishing in Current Biology 16, R156-157, March 7, 2006. DOI 10.1016/j.cub.2006.02.055 www.current-biology.com
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