MHC class II DRB diversity, selection pattern and population structure in a neotropical bat species, Noctilio albiventris.

Abstract

Genes of the major histocompatibility complex (MHC) play a crucial role in the immune response of vertebrates, alter the individual odour and are involved in shaping mating preferences. Pathogen-mediated selection, sexual selection and maternal-fetal interactions have been proposed as the main drivers of frequently observed high levels of polymorphism in functionally important parts of the MHC. Bats constitute the second largest mammalian order and have recently emerged as important vectors of infectious diseases. In addition, Chiroptera are interesting study subjects in evolutionary ecology in the context of olfactory communication, mate choice and associated fitness benefits. Thus, it is surprising that they belong to the least studied mammalian taxa in terms of their MHC diversity. In this study, we investigated the variability in the functionally important MHC class II gene DRB, selection pattern and population structure in the group-living lesser bulldog bat, Noctilio albiventris in Panama. We found a single expressed, polymorphic Noal-DRB gene with clear evidence for positive selection. Roosting colonies were not genetically differentiated, but females showed lower levels of heterozygosity than males, which might be explained by female driven mechanisms of sexual selection. In addition, this study provides the pre-requisites for further investigations of the role of the individual MHC constitution in parasite resistance, olfactory communication and mate choice in N. albiventris and other bats.