Katherine Jack, PhD
Co-Investigator: Jessica Lynch-Alfaro
Approved: December 2010
Original Proposal Abstract:
We will examine the role that the major histocompatibility complex (MHC; also known as human leukocyte antigens) plays in the mating and dispersal decisions of wild white-faced capuchin monkeys (Cebus capucinus) in Santa Rosa National Park (SRNP), Costa Rica. In SRNP, female capuchins are philopatric, males disperse (usually in the company of others), and we see complete changeovers in male group members approximately every four years. This pattern leads to low genetic diversity of BOTH males and females in a given area and a need for maximizing MHC (immune gene) diversity. Our study will investigate the role of the MHC in mate choice and offspring production at three levels: (a) male mate choice through dispersal; (b) female mate choice through copulation timing and possibly through rank influence and; (c) post-copulatory sperm selection for MHC difference/heterozygosity in offspring. We will collect fecal samples from members of six groups (~70), extract genomic DNA from the samples, and use PCR to amplify the MHC class II DRB alleles. Analysis includes: comparisons of allelic similarity across potential and actual mates, allelic similarity of males to females in groups joined vs. neighboring/natal groups, and determining if infants are more heterozygous than expected based on parental profiles (indicating post-copulatory sperm selection). The capuchins at SRNP are an excellent model for the influence of the MHC on human mate choice because they, like humans, appear to have both male and female mate selectivity, engage in non-conceptive sex (mate choice can be compared during conceptive and non-conceptive periods), high sociality and wide dietary breadth, which increases the risk for parasitic and socially contagious infections thereby increasing the importance of dynamic MHC/immune system response.