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 strong target of positive selection in East Asian populations, was driven by the stable availability of aquatic resources in Late Pleistocene northern China. This "nutritional niche construction" suggests that aquatic resources provided essential nutrients like protein, iodine, and zinc, which offset the metabolic costs associated with the allele's effects, such as increased eccrine gland density and hair follicle thickness. The hypothesis is supported by paleoenvironmental, archaeological, and isotopic evidence and offers three testable predictions about spatial, temporal, and isotopic patterns. The study also considers counterexamples to refine the hypothesis, suggesting the allele's advantage is in alleviating nutrient deficiencies rather than enhancing nutrient sufficiency.