The contribution of admixture to primate evolution.

Genome-wide data on genetic variation are now available for multiple primate species and populations, facilitating analyses of evolutionary history within and across taxa. One emerging theme from these studies involves the central role of admixture. Genomic data sets indicate that both ancient gene flow following initial taxonomic divergence and ongoing gene flow at current species boundaries are common. These findings are of particular interest given evidence for a complex history of admixture in our own lineage, including examples of ecologically driven adaptive introgression. Like other aspects of human biology, studies of nonhuman primates thus provide both comparative context and a living model for understanding admixture dynamics in hominins. We highlight several open questions that could be addressed in future work.