Meeting Abstract
The major histocompatibility complex (MHC) plays an important role in adaptive immunity and mate choice in many vertebrate species. Studies in a captive group of mandrills (Mandrillus sphinx) have shown that female mate choice is influenced by the MHC, implying that MHC variability may have important fitness consequences. However, nothing is known about MHC variability in natural populations and how this may play a role in female mate choice. Here, we use next generation sequencing to characterize variation in the mandrill MHC class II DRB loci from 192 fecal samples collected from a wild population in Lopé National Park, Gabon. Our study revealed more than three times the allelic richness previously described in captive mandrills with variants forming two monophyletic clades. Variants in clade 1 (n=106 alleles) exhibit signals of balancing selection, as might be expected under parasite-mediated selection or disassortative mate choice. In contrast, variants in clade 2 (n=29) do not show such a signal and may represent a non-functional pseudogene that has not yet been described in non-human primates, although it has some similarity with the human pseudogene DRB9. We also observe trans-species polymorphism between mandrills and other primates, suggesting that balancing selection has maintained functional MHC lineages beyond speciation events. Future work will use these data to assess the role of the MHC in wild mandrill mate choice and fitness.
