Indian study of genetics of Andaman Islanders uncovers new human ancestor

R. Prasad
The Hindu
Sun, 31 Jul 2016 23:59 UTCMap

© Theierry Falise
The Jarawas.

A study published a few days ago in the journal Nature Genetics has found the presence of a third and a new ancestor to humans — a sibling of the Neanderthal and the Denisovan. The study compared the complete DNA sequences of the Jarawas and the Onges living in the Andaman Islands in the Bay of Bengal with the DNA sequences of Neanderthals and Denisovans, and they found some notable differences in the DNA sequences.

“In this study we have found in the DNA sequence of modern humans, specially in the Jarawa and Onge populations, fragments of DNA that belong neither to the Neanderthal nor the Denisovan nor even to most of the contemporary human groups,” says Partha P. Majumder, one of the corresponding authors of the paper and Director of the National Institute of Biomedical Genomics in Kalyani, West Bengal.

“Further statistical analysis of the DNA segments showed that the best explanation of the origin of these DNA fragments is that they belong to an unknown third human ancestor that is already extinct. The unknown human ancestor is like an evolutionary sibling of the Neanderthal and the Denisovan.”

A small proportion of DNA from the unknown extinct hominin is found only in the population from South and Southeast Asia while it is absent from Europeans and East Asians. “That there is an ancestor of modern humans that was not discovered earlier is a major finding of our work,” he says.