One of the things that is evident in the most recent work on Indian genetics is that some groups, often Brahmin, are enriched for “steppe” ancestry when looking at overall contributions of proximal ancestral components. But, there are other groups that are enriched for “Indus Periphery” ancestry. The plot above takes Indus Periphery on the x-axis, and steppe on the y-axis. You can see that Brahmins are above the main trend, but groups like “Panta Kapu” are below (click the image).
These trends can be hard to spot because of the complexity of the Indian genomic landscape, where geography is not entirely predictive. What explains them?
I outlined my general model in a blog post, The Aryan Integration Theory (AIT). In short, unlike Northern Europe, and like Southern Europe, pre-Indo-European cultural matrices have maintained some robustness in the face of agro-pastoralist intrusion. The persistence of linguistic isolates in the far northwest in the form of Burusho is indicative of this. But also the persistence of the Dravidian language family, which has pre-Aryan roots. The enrichment of “Indus Periphery” ancestry in groups in the west and south, in particular, as well as a Dravidian substrate in toponyms in Gujarat and Maharashtra, and the relative lack of such features in the Gangetic plain, point to the reality that Dravidian speaking peoples are not primal, but their current range is partially reflective of the human geography in the wake of the Indo-Aryan shock on the decaying IVC.