Since this question always comes up at some point, I decided to do a rough back-of-the-envelope calculation of the % steppe across the Indian subcontinent. The way I did it was by taking Pakistan, Bangladesh, and India, and estimating the average percentage from the caste breakdowns (e.g., UP is 20% “upper caste” and 20% “Dalit” and 60% neither, with fractions of steppe/Sintashta about 30%, 10%, and 15%, respectively).
So the final number I came back is that 14% of the ancestry in modern-day South Asia is from the steppe in the form of people descended from Sintashta pastoralists. That is about 220 million human beings worth. You can judge whether that’s significant or not. Additionally, it looks like closer to 20-25% of the Y chromosomes are derived from these people.
I’m not “showing my work” because I think no matter how you estimate it, you’ll get a number in this range. Perhaps 12%. Perhaps 16%. But what difference does that make?
I get a fair amount of email related to questions about Indian genetics, as well as calls for me to adjudicate various controversies. A major problem with any “Aryan invasion theory” or its descendants, which posit non-trivial gene flow from the Eurasian steppe, is the possibility that the Indo-Aryan ancestors of nearly all South Asians (albeit, in extremely varied proportions) were a thousand men with the bright faces, azure eyes, and flaxen locks. Paul Bettany times a thousand astride chariots.
The anachronistic neocolonialism obviously makes Indians uncomfortable. Or that’s my psychoanalysis. I don’t care much either way. What does Lord Indra’s scion care? We are the unbroken lineage, grasping Eurasia’s heart, from the Baltic to the Bay of Bengal!
The flip side of this is people of European ancestry, some of whom are white nationalists, do come close to making this claim. That is, that the Aryans were white Nordic people. The genetics from the Sintashta and Andronovo cultural complexes do indicate that they resemble many of the contemporaneous European populations. Their ultimate locus of origin probably is the Pontic steppe, which is in the geographic boundaries of Europe, as such. Finally, these steppe peoples exhibit genetic signatures of reflux from Europe. That is, they’re not just Yamna-descendants but derived from Yamna-like people who moved west, mixed with local indigenous Europeans, and moved back east along the Eurasian steppe corridor.
Looking at some of the ancient forensic DNA some of these individuals have suggested that I must admit that the Indo-Aryans were genetically like Europeans, and phenotypically like Europeans as well. They know that I won’t lie like some people, and just want me to admit this.