Abstracts (first author)
What drives the rapid regeneration of MHC diversity amongst recently bottlenecked populations?
.Population bottlenecks can restrict variation at functional genes, reducing the ability of populations to adapt to new and changing environments. Understanding how populations generate adaptive genetic variation following bottlenecks is therefore central to evolutionary biology. The major histocompatibility complex (MHC) is a multigene family that provides an ideal model for studying adaptive genetic variation due to its central role in pathogen recognition. While de novo MHC sequence variation is generated by point mutation, gene conversion can generate new haplotypes by transferring sections of DNA within and across duplicated MHC loci. However, the extent to which gene conversion generates new MHC haplotypes in wild populations is poorly understood. We used a 454 sequencing protocol to screen MHC variation across all 13 island populations of Berthelot’s pipit (Anthus berthelotii). The recent colonisation of this species (<75,000 years ago), along with the replicated island system gave us a unique opportunity to identify which MHC alleles were involved in the original colonisation events, and which have been generated in situ, post colonisation. This, in turn, allowed us to identify how new MHC haplotypes have been regenerated across the island populations. In light of these results, I will discuss the roles of mutation, gene conversion and selection in generating and maintaining functional genetic diversity in bottlenecked populations.