Wednesday, December 18, 2013
Scientists present evidence for the accumulation of a Neanderthal DNA region found on chromosome 3 that contains 18 genes, with several related to UV-light adaptation, including the Hyal2 gene
This region was positively selected and enriched in East Asians, ranging from up to 49% in Japanese to 66% in Southern Chinese. The geographic distribution of the Neanderthal genomic region suggests that UV-light mutations were shown to be lost during the exodus of modern human from Africa, and reintroduced to Eurasians from Neanderthals. From 45,000 years to 5,000 years before present, effective population sizes of the Neanderthal region increased at a steady rate. Notably, the growth rate of the effective population size increased at around 5,000 to 3,500 years before present, which suggests a population expansion event. This Asian-specific Neanderthal evolutionary event is also consistent with previous reports of higher levels of Neanderthal ancestry in East Asians than in Europeans.