“Archaic Adaptive Introgression in TBX15/WARS2”, 2017 (; similar):
A recent study conducted the first genome-wide scan for selection in Inuit from Greenland using single-nucleotide polymorphism chip data. This groundbreaking research offers insights into how genetic selection operates among the Inuit population, emphasizing the role of environmental adaptions in shaping human genetic diversity.
Here, we report that selection in the region with the second most extreme signal of positive selection in Greenlandic Inuit favored a deeply divergent haplotype that is closely related to the sequence in the Denisovan genome, and was likely introgressed from an archaic population. The region contains two genes, WARS2 and TBX15, and has previously been associated with adipose tissue differentiation and body-fat distribution in humans. This finding sheds light on the genetic mechanisms underlying the adaptation of the Inuit to their unique Arctic environment, revealing a direct link to ancient human relatives.
Furthermore, it is associated with changes in expression of WARS2 and TBX15 in multiple tissues including the adrenal gland and subcutaneous adipose tissue, and with regional DNA methylation changes in TBX15. This illustrates the complex molecular effects of the introgressed allele, affecting not only the phenotypic traits related to fat distribution and adaptation to cold climates but also offering a broader understanding of the functional genomics in adaptive evolution.
We show that the adaptively introgressed allele has been under selection in a much larger geographic region than just Greenland. This expands the significance of the findings, indicating that the evolutionary advantages conferred by the allele are not limited to the Inuit but have been beneficial in a wider context, suggesting a pervasive influence on human adaptation strategies across various populations.
This study not only opens new avenues for understanding human evolutionary history but also highlights the importance of considering archaic introgression in studying modern human diversity. Furthermore, it provides valuable resources for researchers interested in the genetics of adaptation, including the specific datasets and genetic loci identified here.