The first animal model of recent human evolution reveals that a single mutation produced several traits common in East Asian peoples, from thicker hair to denser sweat glands, an international team of researchers report.
The team, led by researchers from Harvard Medical School, Harvard University, the Broad Institute of MIT and Harvard, Massachusetts General Hospital, Fudan University and University College London, also modeled the spread of the gene mutation across Asia and North America, concluding that it most likely arose about 30,000 years ago in what is today central China.
The findings are reported in the cover story of the 14 February issue of Cell.
"There are three parts to this study" said Professor Mark Thomas, UCL Research Department of Genetics, Evolution and Environment, and an author on the paper.
"The first links the version of the EDAR gene common in East Asians to a set of traits including thicker hair and a higher density of sweat glands; the second uses computer simulation to identify where and when the mutation is likely to have arisen, and what its selective advantage was likely to be; and the third showed that when the East Asian version of the gene is inserted into a mouse, that mouse exhibited many of the same traits as those it is linked with in humans".
Previous research in Pardis Sabeti's lab at Harvard University had identified the mutation as a strong candidate for positive selection. That is, evidence within the genetic code suggested the mutant gene conferred an evolutionary advantage, though what advantage was unclear.
The mutation was found in a gene for ectodysplasin receptor, or EDAR, part of a signalling pathway known to play a key role in the development of hair, sweat glands and other skin features. While human populations in Africa and Europe had one, ancestral, version of the gene, most East Asians had a derived variant, EDARV370A, which studies had link
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