There are lots of strange takes on the India Today piece, 4500-year-old DNA from Rakhigarhi reveals evidence that will unsettle Hindutva nationalists. I’m friendly with the author and saw an early draft. So I’m going to address a few things.
The genetic results are becoming more and more clear. A scaffold is building and becoming very firm. In the 2020s there will be a lot of medical genomics in India. But before that, there will be population genetics. Ancient DNA will be the cherry on the cake.
Here’s what genetics tells us. First, a component of South Asian ancestry, especially in North India, and especially in North Indian upper caste groups, seems to be the same as ancient agro-pastoralists who ranged between modern Ukraine and modern Tajikistan. Genetically, these people are very similar to certain peoples of Central and Eastern Europe of this time, though there is a varied dynamic of uptake of local Central Eurasian elements as they ranged eastward.
This ancestral component is often called “steppe.” This ancestral component is a synthesis of ancient European hunter-gatherer, Siberian, and West Asian. The steppe component seems to arrive in Central and South Asia after 2000 BC.
Second, another component of South Asian ancestry is very distinctive to the region. It is deeply but distantly related to branches of humanity which dominate Melanesia and eastern Eurasia, up into Siberia. The magnitude of the distance probably dates to ~50 thousand years ago, when the dominant element of modern humans expanded outward from West Asia, east, north, and west. These people are called “Ancient Ancestral South Indians,” or AASI. Their closest relatives today may be the natives of the Andaman Islands, but this is a very distant relationship.
AASI is the dominant component of what was once called “Ancestral South Indians,” or ASI. It turns out that “ASI” themselves were a compound synthetic population. This was long suspected by many (e.g., David W.). What was ASI a compound of? About ~75 percent of its ancestry was AASI, but the balance seems to have been a West Eurasian component related to farmers from western Iran. We can call this group “farmers.”
With a few samples from outside of the IVC region, and one (or two) samples from within the IVC region, geneticists are converging upon the likelihood that the profile in the greater IVC region before 2000 BC was a compound of these farmers with the AASI. But even within the IVC region, there seems to have been a range of variation in ancestry. The IVC was a huge zone. It may not have been dominated by a single ethnolinguistic group (even today there is the Burusho linguistic isolate in northern Pakistan). Note that the much smaller Mesopotamian civilization was multiethnic, with a non-Semitic south and a Semitic north (Sumer and Akkad).
The key point is that it is very likely the IVC lacked the steppe ancestral component. That it did have AASI component. And, it did have a farmer component with likely ultimate provenance in western Iran. Additionally, there were smaller components derived from pre-steppe Central Eurasian people.
While the steppe people arrived in the last 4,000 years, and at least some of the ancestors of the AASI are likely to have been in South Asia for 40,000 years, the presence of the AASI-farmer synthesis genetically is conditional on when a massive presence of western farmers came to affect the northwestern quarter of South Asia. It seems unlikely to have been before Mehrgarh was settled 8,500 years ago. The genetic inferences to estimate the time of admixture between AASI and farmer are currently imprecise, but it seems likely to have begun at least a few thousand years before 2000 BC. range of 8,500 and 6,000 years ago seems reasonable.
So 4,000 years ago the expanse of the IVC was dominated by a variable mix of farmer and AASI. One can call this “Indus Valley Indian” (IVI).
Just like ASI, there was an earlier abstract construct, “Ancestral North Indian” (ANI). Today it seems that that too was a compound. To be concise, ANI is a synthesis of steppe with IVI. The Kalash of northern Pakistan are very close genetically to ANI. This means that while ASI had West Eurasian ancestry, albeit to a minor extent. And ANI had AASI ancestry, albeit to a minor extent. The main qualitative difference is that ANI had a substantial minority of steppe ancestry.
To a great extent, the algebra of genetic composition across South Asia can be thought of as modulating these three components, farmer, steppe, and AASI.* Consider:
- Bhumihar people in Bihar tend to have more steppe than typical, but not more farmer than typical, and average amounts of AASI.
- Sindhi people in Pakistan tend to have lots of farmer, some steppe, and not much AASI.
- Reddy people in South India have lots of farmer, very little steppe, and average amounts of AASI.
- Kallar people in South India have some farmer, very little steppe, and lots of AASI.
For details of where I’m getting this, you can look at The Genomic Formation of South and Central Asia for quantities. But as a stylized fact farmer ancestry tends to peak around the Sindh. In Pakistan steppe ancestry increases as you go north. As you go east and south AASI increases pretty steadily, but there are groups further east, such as Jatts and Brahmins, who have a lot of steppe, almost as much as northern Pakistani groups. And curiously you get a pattern where some groups have more steppe and AASI, and less farmer, than is the case to the west (you see this in the Swat valley transect, as steppe & AASI increase in concert).
Going back to the history, by the time the steppe people arrived in South Asia, in the period between 2000 BC and 1000 BC, it may be that the IVI ancestry is what they mixed with predominantly. Though it is likely that the southern and eastern peripheries had “pure” AASI, by the time steppe people spread their culture to these fringes they were already thoroughly mixed with IVI populations, and so already had some AASI ancestry.
In contrast, the farmer populations likely mixed extensively with AASI in situations where the two populations were initially quite distinct.
Please note I have not used the words “Aryan” or “Dravidian.” The reason is that these are modern ethnolinguistic terms. Genetics is arriving at certain truths about population changes and connections, but we don’t have a time machine to go back to the past and determine what language people were speaking 4,000 years ago.
Our inferences rest on supposition, and a shaky synthesis of historical linguistics and archaeology and genetic demography, a synthesis which is unlikely to ever be brought together in one person due to vast chasm of disciplinary method and means.
It is highly likely that the steppe component is associated with Indo-European speaking peoples. Probably Indo-Aryan speaking peoples. The reason is that by historical time, the period after 1000 BC, Iran and Turan seem to already have been dominated by Indo-Iranian peoples. But, in the period around 2000 BC, western Iran was not Indo-Iranian. People like the Guti and the Elamites were not Indo-European, and they were not Semitic. We have some genetic transects which show that steppe ancestry did arrive in parts of Turan and Iran in the period after 2000 BC.
Where did the Dravidian languages come from? We don’t know. They could have been spoken by an AASI group. Or, they could be associated with farmers from the west. We don’t know. Ultimately, we may never know. Unlike Indo-European languages, there are no Dravidian languages outside of South Asia.
Various toponymic evidence indicates that Dravidian languages were spoken at least as far north and west as Gujurat. And Brahui exists today in Balochistan. Though I don’t have strong opinions, I think Dravidian languages probably are descended from a group of extinct languages that were present in Neolithic Iran.
Though unlike Indo-Aryan languages, Dravidian exploded onto the scene after a long period of incubation within South Asia, as part of at least one of the language groups dominant with the IVC and pre-IVC societies.
At least that’s my general assessment. I have strong opinions about the genetics. But am much more curious about what others have to say about linguistics and archaeology.
* Some groups, such as Munda and Indo-Aryan groups in Northeast India, have East Asian ancestry. Some groups in coastal Pakistan have African ancestry.
