Project Summary In the last thirteen years, analysis of ancient genomes suggests that population admixtures are a dominant feature of human history. Admixture between populations leads to genetic exchange between populations, and this provides an opportunity to introduce new genetic variation much more rapidly than waiting for mutations to occur naturally. Analysis of Neanderthal, Denisovan and ancient modern human genomes suggests that admixture has occurred at different time scales in the past. We are only beginning to understand how genetic variation that is introduced during an admixture event has been evolving in the recipient populations. Evolutionary forces like demographic history and natural selection will also affect the frequency distributions of these mutations in recipient populations. The goal of this research project is to develop statistical methods and computational approaches that can be applied to admixed genomes to investigate how admixture shapes patterns of genetic variation and how it facilitates adaptations. As admixed genomes are mosaics of different ancestries, we can study genetic variation in these genomes to gain insights into the histories of both recipient and donor populations. For example, we can identify genetic variation that help recipient populations adapt to new environments. We will also leverage genetic patterns of admixed genomes to characterize how natural selection acted on genetic variation after very recent admixture events. Finally, with our methods, we can also gain insight into the structure present in the donor populations even if only a handful of genomes exists for these populations. In summary, the methods and the empirical approaches proposed here will be useful to elucidate how different contributions from a complex web of population interactions has affected the evolution of our species.