How an organism interacts with its environment influences its exposure to disease; in response, organisms have evolved a variety of immune responses. However, there have been few inquiries into the effect of ecology on the evolution of immune genes outside of primates. In this study we will examine the effect of ecological traits on the evolution of immune genes in bats. Bats are an ideal system because, as the second largest mammalian order, they exhibit a wide variety of diets, roost habits, group sizes and mating systems and host numerous viruses, bacteria and eukaryotic parasites. This work will help identify which ecological traits put groups at the greatest disease risk and shed light on how bats survive infection by pathogens that are lethal to humans. The findings of this research will assist conservationists in preserving species of concern and the ecosystem services they provide. The results will also be directly useful to the public health community and reveal potential targets for disease intervention research.
The researchers will test whether the immune genes of bats that frequently contact other bats or come into contact with other animals are evolving under greater pressure than those with lower disease risk (less contact). They will sequence multiple immune genes from multiple species, with a focus on the ecologically diverse Neotropical bat family Phyllostomidae. Using targeted sequence capture and next generation sequencing techniques, they will obtain information from multiple immune genes, representing both the innate and adaptive immune system and responses to viruses and extracellular pathogens. The genetic information collected will be combined with ecological data while accounting for evolutionary history to discover how bats have evolved their immunity in response to the pathogens of their environment. The examination of multiple immune genes will allow a more comprehensive characterization of immune evolution than single gene studies, reducing the risk of missing positive selection that does not act on certain genes and demonstrating general patterns in ecologically relevant immunogenetic evolution. The particular residues under selection revealed by this study will become important targets for functional studies into the exact nature of the coevolutionary arms race between bats and their pathogens.
