This award is for a postdoctoral fellowship. The investigator will study the genetic adaptations of arctic mammals and their response to the effects of climate change. Using existing tissue samples of terrestrial and marine mammals, the investigator will screen for linkage disequilibrium in the major histocompatibility complex loci. This disequilibrium often indicates a reduction in genetic diversity and thus greater susceptibility to disease and foreign pathogens. Several alternative hypotheses will also be tested. This work has implications for the effects of climate change on typically isolated arctic mammals, as temperate species undergoing range expansion could introduce a broader range of diseases.