Brief communication: Population data support the adaptive nature of HACNS1 sapiens/neandertal-chimpanzee differences in a limb expression domain.

The 546-base pair enhancer of limb expression HACNS1, which is highly constrained in all terrestrial vertebrates, has accumulated 16 human-specific changes after the human-chimpanzee split. There has been discussion whether this process was driven by positive selection or biased gene conversion, without considering population data. We studied 83 South Amerindian, 11 Eskimo, 35 Europeans, 37 Bantu, and non-Bantu Sub-Saharan speakers, and 28 Brazilian mestizo samples and found no variation in this DNA region. Similar lack of variability in this region was found in four Africans, five Europeans or Euro-derived, two Asians, one Paleo-Eskimo, and one Neandertal sequence, whose whole genomes are publicly available. No difference was found. This result favors the interpretation of past positive and present conservative selection, as would expected in a region which influences Homo-specific traits as important as opposable thumbs, manual dexterity, and bipedal walking. Am J Phys Anthropol, 2010.