I've mentioned a few times that the Reich lab has been finding suggestive evidence for admixture between indigenous South Asians and a West Eurasian group on the order of ~3,000 years before the present. The modal explanation is probably an Indo-Aryan intrusion. Dienekes used rolloff in ADMIXTOOLS to repeat these general findings. Specifically,
he found signal for an admixture event analogous to one between non-Brahmin South Indians and Northern Europeans.
I say analogous because I do not mean to imply that the admixture was exactly of this form. Rather, there are general resemblances in the genetic profiles across the four groups (i.e., Orcadian & North Kannadi, and population X and Y which merged to form South Indian Brahmins). The only thing I would add is that the North Kannadi, representative of non-Brahmin South Indians, are themselves a mixture between West Eurasian and an indigenous South Asian population. And, looking at ...