Tony Joseph has an interesting piece up, Who built the Indus Valley civilisation?, which people are asking me about via email. First, I don’t have any inside information. Last I heard in September was that the Rakhigarhi results were “one or two months away,” like they have been for a year or so. So I put it out of mind.
In any case, here are the important points:
All this could now change thanks to the science of genetics and four ancient skeletons excavated from a village called Rakhigarhi in Haryana. The four people to whom these bones once belonged — a couple, a boy and a man — lived roughly 4,600 years ago when the Indus Valley civilisation was in full bloom.
In the three-and-a-half years since its excavation, Shinde has brought together scientists from Indian and international institutions like the Centre for Cellular and Molecular Biology, Hyderabad (CCMB), Harvard Medical School, Seoul National University, and the University of Cambridge to work on different parts of the project, including extracting and analysing DNA from these ancient people, reconstructing their faces, and studying the remains of their habitation to understand their daily habits and ways of life.
The DNA analysis will also help figure out their height, body features, and even the colour of their eyes….
Harvard Medical School suggests to me they finally got David Reich’s group involved.
As for Cambridge University, Eske Willerslev now has an appointment there. He’s apparently assembling a paleogenetics group.
The piece specifically highlights Y and mtDNA. But if they are talking about height, body features, and color of eyes, they must have gotten genome-wide data.
If Eske Willerslev is involved they may have sequenced the whole genome at some coverage of at least one of the samples.
If I had to bet I think the Rakhigarhi samples will be Y haplogroups J2 or the Indian branch of L, and the mtDNA will be an Indian branch of M. In terms of genome-wide patterns they will exhibit a mixture between West Eurasian ancestry, with strong affinities to Near Eastern farmers from the Zagros, and what we now term “Ancestral South Indians” (AS), who descend from the aboriginal peoples of the subcontinent, and are genetically somewhat closer to East Eurasians than West Eurasians (to be fair, I think it is not implausible that much of ASI heritage is the product of westward migration out of Southeast Asia during the Pleistocene and early Holocene).
Overall, genetically these samples may look the most like South Indian non-Brahmin middle-to-upper castes. Think the Reddy people of Andhra Pradesh. Additionally, going back to R1a1a-Z93, I do think it was intrusive with the Indo-Aryans. Its highest frequencies do tend to be among upper castes, and there is an increasing cline toward the northwest of the subcontinent.
ButR1a1a-Z93’s presence at appreciable frequencies in South India among non- Brahmins, including tribal populations, indicates a more complex ethnogenesis of Dravidian speaking groups than we might have realized. Priya Moorjani told me specifically that 4,000 years ago there were “unmixed ANI and ASI groups” in the subcontinent. I think for the former she’s picking up the signal of intrusive Indo-Aryans. But what about the latter? I doubt there were unmixed ASI in the Indus Valley. But they probably still persisted to the south and east when the Indus Valley people were in decline and the Indo-Aryans arrived. The South Indian Neolithic dates from 3000 to 1400 BC.
Here my moderate confidence sketch. The collapse of the Indus Valley civilization was probably ultimately due to the fact that these early antique societies were not very robust to exogenous shocks and endogenous decay of asabiya. Once these societies, which have accumulated some level of surplus wealth by squeezing it out of the Malthusian margin, start to totter social collapse and dissolution can happen fast, and barbarian groups outside of the gates with more social cohesion can engage in a takeover.
In the case of the collapse of the Sumerian-Akkadian civilization, the barbarian Amorites actually took over and maintained cultural continuity. In post-Roman Britain, the Roman civilization collapsed in totality, and “Roman Christianity” had to be reintroduced from the European continent and from the Celts into Anglo-Saxon England. The barbarian takeover resulted in the total cultural obliteration of the Britons. Finally, you have instances such as post-Roman Gaul, which transformed into Francia. Unlike the case of the transition from the rule of the Third Dynasty of Ur to that of the Amorites, the Frankish rulers oversaw a wholesale reimagining of the identity of the people of Gaul. Even as late as 800, a ruler such as Charlemagne still spoke a dialect of German as his first language. And yet the Franks of Neustria were ultimately transformed and became one with the “Romans” whom they ruled.
In the post-Harappan world of northwest India I suspect something close to the Anglo-Saxon precedent is likely. Though the majority of the ancestry of the Upper Gangetic plain is not Indo-Aryan, a substantial proportion is. And this ancestry is detectable at lower fractions even among non-Brahmin Bengalis. In Central and South India the situation was probably more like Mesopotamia around ~2000 BC or Gaul post-500 AD. There were various sorts of interactions between Indo-Aryans and local populations, as well as the final assimilation of aboriginal peoples into Indo-Aryan and Dravidian speaking peoples.*
* The Munda people clearly have some East Asian ancestry. And, they are mostly a mix of ANI and ASI. But whenever I look at their genome-wide results it strikes me they may not have any Indo-Aryan ancestry. This may ultimately be totally comprehensible in light of the chronology of migration and segregation.
Update: One of the researchers involved indicates Eske Willerslev is not involved.