AsianScientist (Jan. 6, 2014) – A new study has shown how a specific mutation in the SLC24A5 gene provides evidence of shared ancestry of Asians with Europeans.
While the genetics of skin color is largely unclear, past research using zebrafish by Pennsylvania State University College of Medicine’s Keith Cheng identified that the SLC24A5 gene is a key contributor to the skin color difference between Europeans and West Africans.
In this study, Victor Canfield, assistant professor of pharmacology, together with Cheng, studied a specific mutation in SLC24A5, called A111T.
The researchers found that all individuals from the Middle East, North Africa, East Africa and South India who carry the A111T mutation share a common “fingerprint” – traces of the ancestral genetic code – in the corresponding chromosomal region, indicating that all existing instances of this mutation originate from the same person.
The pattern of proportions of people with this lighter skin color mutation indicates that the A111T mutation occurred somewhere between the Middle East and the Indian subcontinent.
“This means that Middle Easterners and South Indians, which includes most inhabitants of India, Pakistan and Bangladesh, share significant ancestry,” said Cheng.
This mutated segment of DNA was itself created from a combination of two other mutated segments commonly found in Eastern Asians – traditionally defined as Chinese, Japanese and Korean.
“The coincidence of this interesting form of evidence of shared ancestry of East Asians with Europeans, within this tiny chromosomal region, is exciting,” said Cheng. “The combining of segments occurred after the ancestors of East Asians and Europeans split geographically more than 50,000 years ago; the A111T mutation occurred afterward.”
These findings were reported in the journal G3.
Cheng plans to next look at more genetic samples to better understand what genes play the most important role in East Asian skin color. He will then use zebrafish to test those suspected genes.
The article can be found at: Canfield V et al. (2013) Molecular Phylogeography of a Human Autosomal Skin Color Locus Under Natural Selection.
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Source: Pennsylvania State University; Photo: 21TonGiant/Flickr/CC.
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