Science – Page 4 – Brown Pundits

Indian media is finally reporting on the Aryan migration into South Asia

For various ideological reasons in India there has been a strong resistance to the idea that Aryans came from outside of South Asia. When David Reich’s Reconstructing Indian Population History was published 2009 the Indian media had a weird response. For example, Aryan-Dravidian divide a myth: Study.

Though Reich’s paper was equivocal, it was clear to me that it was likely going to be the launching point for a resurrection of the Aryan migration theory. Now Tony Joseph in The Hindu has published a pretty good survey of the literature, How genetics is settling the Aryan migration debate. Nothing new for readers of this weblog, but he some good quotes:

The avalanche of new data has been so overwhelming that many scientists who were either sceptical or neutral about significant Bronze Age migrations into India have changed their opinions. Dr. Underhill himself is one of them. In a 2010 paper, for example, he had written that there was evidence “against substantial patrilineal gene flow from East Europe to Asia, including to India” in the last five or six millennia. Today, Dr. Underhill says there is no comparison between the kind of data available in 2010 and now. “Then, it was like looking into a darkened room from the outside through a keyhole with a little torch in hand; you could see some corners but not all, and not the whole picture. With whole genome sequencing, we can now see nearly the entire room, in clearer light.”

In relation to online debates I have had Indian interlocutors tell me flat out that they believe in the papers published between 2005 and 2010. It is nice to get the scientists who actually published this work now admit that new results overturn the older theories.

Note: I am going to refer to this as a migration, because “invasion” seems to connote too much specificity as to how it happened. But I have a difficult time imagining that it was a peaceful process.

The last days of pre-ancient DNA Indian population genomics

If anyone wants to know about the population genetics of South Asia, I recommend three papers (all are open access):

– Genetic Evidence for Recent Population Mixture in India

– A genetic chronology for the Indian Subcontinent points to heavily sex-biased dispersals

– The promise of disease gene discovery in South Asia

In the near future ancient DNA will do for South Asia what has been done for Europe, and to a lesser extent the Near East. It will pull back our veil of ignorance. But until then we have genomic inference from larger data sets with a greater number of markers. What can we say now?

– The 2009 work that modern South Asians are broadly a compound of two streams of the out of Africa populations is correct. One is much like other West Eurasians. Another is distantly related to other East Eurasians, with possible affinities to Paleolithic Southeast Asian hunter-gatherers.

– The West Eurasian ancestry of South Asians, the “Ancestral North Indians” (ANI), does likely seem to be a mixture at minimum between two groups. One element is related to the eastern farmers who first adopted agriculture on the slopes of the Zagros ~10,000 year ago. Another stream is closely related to the Yamna people who flourished on the Eurasian steppe north of the Black Sea ~5,000 years ago.

– The Munda peoples seem to have a distinct Southeast Asian component that ties them with other Austro-Asiatic peoples. Their migration was almost certainly tied to the Neolithic migration of rice farmers. They are likely not the primal aboriginals of South Asia.

– The R1a1a-Z93 Y chromosomal lineage found across much of South Asia, and especially the higher castes and the north, increased in frequency within the last 4,000 years. It is almost certainly exogenous to South Asia; ancient DNA from the steppe finds the Z93 in Iranic peoples, but no Indian ancestry in these groups.

As I said, ancient DNA will clarify lots of things. I expect that to happen in the next few years.