Nutritional Niche Construction and Local Adaptation: The Aquatic Resource-Driven Hypothesis of EDAR V370A in East Asia

The study proposes that the EDAR V370A allele, a significant target of positive selection in East Asian populations, was driven by the stable availability of aquatic resources in Late Pleistocene northern China. This hypothesis suggests that these resources, rich in protein and trace elements like iodine and zinc, provided a selective advantage by offsetting the metabolic costs associated with the allele's pleiotropic effects, such as increased eccrine gland density, hair follicle thickness, and mammary branching. The framework of "nutritional niche construction" is introduced, supported by paleoenvironmental, archaeological, and isotopic evidence. The hypothesis is testable through predictions about spatial correlation, temporal dynamics, and isotopic signatures, and it suggests that the allele's advantage lies in "alleviating deficiency" rather than "augmenting sufficiency." This offers a new perspective on local adaptation and phenotypic differentiation in East Asian populations.