In light of all the posts on Indian genetics, and my soon-to-be conversation with Vagheesh Narasimhan, I thought I would lay out some things in a single post rather than scattering across comments.
* I dislike the political/tribal valences of questions about South Asian genetic and cultural history. As an American, I’m very detached from the whole thing. As someone with an Islam-skeptic view (I have posted my sketches of Muhammad being sodomized by a camel on this weblog), I also am not someone who thinks that the Muslim impact on India was wholly good. Some of you lower IQ Hindu nationalists detect an Islamic subtext in my comments…but you just stupid and biased (which is OK, since most people are stupid, and everyone is biased). What you are detecting is that I generally find some of the anti-Islamic perspectives of Hindu nationalists ahistorical as well, and, strangely almost enslaved and haunted by Islam.
For example, while some Hindu nationalists linger on the violent and avaricious nature of the Turks and its impact on India as sui generis, I am quite amazed the more I think about it and read about it that Indian religio-cultural systems persisted so robustly. Islam is nothing special, just a flavor of another thing.
* As someone of the Right, I am not a fan of Marxism, though some Marxist analysis and historiography is useful. That being said, some on the Indian Left, Marxist and not, seem to support the migration-narrative for the “wrong reasons.” This includes some Indian scientists I follow on Twitter.
It’s pretty depressing when biologists spread scientific results not because the results themselves were interesting, but because of second-order impacts on internecine political arguments. Those second-order impacts happen to be that for whatever reason the Hindu Right as adhered itself to a set of positions that are difficult to support empirically, which have only ethereal and tenuous connections to Hindu nationalism.
Though I am probably more suspicious of Marxism than most, I am also not someone who thinks all Hindu nationalists are Nazi and that that position is ipso facto illegitimate. Not all positions and ideologies I disagree with are illegitimate.ย
* The empirical data on migration of large numbers of pastoralists into South Asia between 2000 and 1500 BC seems very strong now. Before 2010 I assumed that something like this happened, but that it was a matter of a few percents. That is, I had assumed that the Indo-Aryan migration was likely as demographically impactful as the Magyar conquest of modern Hungary. Not very.
In 2009 Reconstructing Indian History was published. I also began examing genome-wide data myself. In short, South Asians were way too “West Eurasian” in relation to my earlier assumptions. I didn’t know what to make of it. Reconstructing Indian History presented a model where there had been a massive admixture between “Ancestral North Indians” and “Ancestral South Indians.” In personal communication of the authors explained just how similar “ANI” was to other West Eurasians (pairwise Fst). It seemed then that the admixture had happened during the Holocene.
* Looking at packages like Treemix and Admixture as 2010 progressed many were arguing that ANI was two populations. I saw it myself in my analyses. Follow-ups from the Reich lab confirmed this hunch. Some South Indian populations shared drift with Georgians/Armenians, while some North Indian populations (e.g., UP Brahmins) shared a lot of drift with Northeast Europeans and ancient steppe people.
* Model-based analyses today suggest that 10-15% of the ancestry of modern South Asians is “steppe.” In some groups, it is nearly 30% (Jatts, Kalash, some North Indian Brahmins). This is a huge demographic impact.
Like many of the authors, the confluence of linguistic affinities between Eastern Europeans and Indo-Aryans and the genetic affinities point to a recently shared origin. As South Asians have ancestry components (AHG in particular) that Eastern Europeans do not, the most parsimonious explanation is that Eastern Europeans or their ancestors are a donor population to South Asians.