“The Genomics of Human Local Adaptation”, 2020-04-14 (; similar):
Local adaptation has critically contributed to the (modest) genetic and phenotypic differentiation that exists among human groups, including in health-related traits that contribute to population health disparities.
Local adaptation has happened on alleles of diverse origin (on new, pre-existing, and introgressed alleles) and through diverse mechanisms (monogenic and polygenic adaptation).
Ancient DNA will play a key role in our understanding of local adaptation by improving inferences of past events. Further, it has revealed the importance of adaptive introgression, by which modern humans acquired adaptive alleles from archaic humans.
Novel analysis methods will improve our power to identify targets of local adaptation, especially those with weak signatures. Combining genetic and environmental information promises to improve the identification of genomic targets and the corresponding selective force.
Modern humans inhabit a variety of environments and are exposed to a plethora of selective pressures, leading to multiple genetic adaptations to local environmental conditions. These include adaptations to climate, UV exposure, disease, diet, altitude, or cultural practice and have generated important genetic and phenotypic differences amongst populations. In recent years, new methods to identify the genomic signatures of natural selection underlying these adaptations, combined with novel types of genetic data (eg. ancient DNA), have provided unprecedented insights into the origin of adaptive alleles and the modes of adaptation. As a result, numerous instances of local adaptation have been identified in humans. Here, we review the most exciting recent developments and discuss, in our view, the future of this field.
[Keywords: genetic adaptation, positive selection, selection on de novo mutation (SDN), selection on standing variation (SSV), adaptive introgression, polygenic selection, genetic-environmental correlation, genealogical methods]