Neanderthal adaptive introgression shaped LCT enhancer region diversity without linking to lactase persistence in East Asian populations

Abstract

Positive selection at the 2q21.3 locus in Europeans and Africans has long been tied to lactase persistence (LP) and milk-drinking and is a textbook example of convergent evolution and gene–culture coevolution. However, the selection may not have been driven by LP alone. Here, we identified a high-frequency East Asian–specific haplotype at this locus, which came from Neanderthals and has been under positive selection. While this haplotype might be linked to LP, it is highly unlikely that the selection would have been for this reason. Instead, changes in immune function likely explain the selection in East Asians, thus indicating that selection was either for different reasons in different populations or selection was similarly not for LP in other populations. Keywords: LCT, adaptive introgression, Neanderthal, East Asian, lactase persistence