Human Adaptations to Diverse Environments

The history of human evolution and dispersal was associated with remarkable environmental challenges to those processes that maintain stable physiological conditions.  Indeed, environmental change over time and over space has been a major feature of human evolution. Though many adaptations undoubtedly occurred at the cultural and behavioral levels, the striking variation of human phenotypes suggests that adaptations also involved genetic changes.  Cultural changes, e.g. different modes of subsistence or diets, in turn created new selective pressures. We have developed approaches for test for the impact that selective pressures associated with specific environmental factors have had on the human genome. Using these approaches, we identify adaptations to selective pressures related to climate as well as diet and subsistence. Some of these beneficial alleles were selected in multiple continents while others represent continent-specific adaptations.  Interestingly, many alleles strongly correlated with climate variables also influence risk to diseases of the immune response.