The 85th Annual Meeting of the American Association of Physical Anthropologists (2016)

A novel approach for detecting adaptive introgression in modern humans


1MCB, University of California Merced, 2IB, University of California Berkeley

April 14, 2016 2:00, Imperial Ballroom B Add to calendar

Comparisons of DNA from archaic and modern humans show that modern and archaic humans interbred, and in some cases received an evolutionary advantage from doing so. This process, adaptive introgression (AI), may lead to a faster rate of adaptation than is predicted from models with mutation and selection alone. Within the last couple of years, a series of studies have identified regions of the genome that are likely examples of AI. In many cases, once a region was ascertained as being introgressed, commonly used statistics based on both haplotype as well as frequency information were employed to test for positive selection. Introgression by itself, however, changes both the haplotype structure and the distribution of allele frequencies, and these are the patterns that many methods use to detect selection. Therefore, patterns generated by introgression alone may lead to false inferences of positive selection. Here we use simulations to investigate the false positive rate of these statistics under null models that include introgression and examine known examples of AI to discover new statistics that can specifically differentiate between introgression and adaptive introgression. We then examine the 1000 Genomes data to identify regions under adaptive introgression.