Environmental selection during the last ice age on the mother-to-infant transmission of vitamin D and fatty acids through breast milk
Abstract
The frequency of the human-specific EDAR V370A isoform is highly elevated in North and East Asian populations. The gene is known to have several pleiotropic effects, among which are sweat gland density and ductal branching in the mammary gland. The former has led some geneticists to argue that the near-fixation of this allele was caused by selection for modulation of thermoregulatory sweating. We provide an alternative hypothesis, that selection instead acted on the allele's effect of increasing ductal branching in the mammary gland, thereby amplifying the transfer of critical nutrients to infants via mother's milk. This is likely to have occurred during the Last Glacial Maximum when a human population was genetically isolated in the high-latitude environment of the Beringia.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- May 2018
- DOI:
- 10.1073/pnas.1711788115
- Bibcode:
- 2018PNAS..115E4426H