Forgot to highlight one of the coolest abstracts from SMBE 2012, A genomewide map of Neandertal ancestry in modern humans:
2. The map allows us to identify Neandertal alleles that have been the target of selection since introgression. We identified over 100 regions in which the frequency of Neandertal ancestry is extremely unlikely under a model of neutral evolution. The highest frequency region on chromosome 4 has a frequency of Neandertal ancestry of about 85% in Europe and overlaps CLOCK, a key gene in Circadian function in mammals. The high frequency, Neandertal-derived variant is specific to Europeans; it is not very common in East Asians. This gene has been found in other selection scans in Eurasian populations, but has never before been linked to Neandertal gene flow
One of the predictions of assimilation of a large intrusive population with a small but long endemic population is that there will be biased representation of adaptive alleles from the latter into the former. In other words, if genome-wide admixture is on the order of 5% from the latter into the former, alleles which confer local fitness benefits will be present in the descendants of the asymmetric admixture in proportions of out …