Ecological Drivers of Genomic Disease Adaptation in Mammals
Habitats exert direct effects on the evolutionary trajectories of species that live in them. Often we do not know the most important elements of the environment driving these pressures, which may impact our understanding of the expected evolutionary impacts of modern environmental changes. During my NSF Fellowship funded postdoc, I am using the footprints of past selection pressures, in the form of genomic signals of natural selection, to understand how ecological and life history factors have affected pathogen exposure.
The conditions leading to disease outbreaks can be understood from the epidemiological triad: the interactions of host, pathogen, and environment. To understand these complex interactions on more than a piecemeal basis, we must simplify: I modified the epidemiological triad to collapse the host and pathogen variables into the genomic effect of pathogen exposure, measured by selection on virus interacting proteins (VIPs). The number of potential ecological effects and their interactions is still complex, so despite using a large data set (>230 mammal genomes), it was useful to carefully develop Bayesian statistical models to determine the most important ecological factors. Among other influences on past pathogen exposure, I found important effects of climate, overlapping species ranges, and individual viral traits. In this way I combine elements of the fields of evolutionary genomics and disease ecology to improve our understanding of disease exposure, with implications for predicting future changes to pathogen prevalence with climate change.