Estimating a date of mixture of ancestral South Asian populations:
Linguistic and genetic studies have shown that most Indian groups have ancestry from two genetically divergent populations, Ancestral North Indians (ANI) and Ancestral South Indians (ASI). However, the date of mixture still remains unknown. We analyze genome-wide data from about 60 South Asian groups using a newly developed method that utilizes information related to admixture linkage disequilibrium to estimate mixture dates. Our analyses suggest that major ANI-ASI mixture occurred in the ancestors of both northern and southern Indians 1,200-3,500 years ago, overlapping the time when Indo-European languages first began to be spoken in the subcontinent. These results suggest that this formative period of Indian history was accompanied by mixtures between two highly diverged populations, although our results do not rule other, older ANI-ASI admixture events. A cultural shift subsequently led to widespread endogamy, which decreased the rate of additional population mixtures.
I’m not sure I believe this. To reiterate my model:
– ~10,000 years ago South Asia was inhabited by peoples with an ancient affinity to the Andaman Islanders, and a closer relationship to East Eurasians than West Eurasians.
– >10,000 years ago a major intrusion into the subcontinent occurred from West Eurasia. More specifically, these were West Asians who began at Mehrgarh.
– ~5,000 years ago a major intrusion into the subcontinent occurred from Southeast Asia. There were the Austro-Asiatic ancestors of the Munda, who brought rice. They admixed with the population which had emerged from the hybridization of the Mehrgarhans and the indigenous South Asians.
– ~3,500 years ago the Indo-Aryans arrived. Their origins were further north than the Mehrgarhans in Western Eurasia. They left a stamp on all Indo-European South Asians, but not on Dravidian speaking or Munda groups.
As a minor sidenote it may be fallacious to assume that the arrival of agriculture in India resulted in the spread of one language family. It may be that there were several colonizations from several West Asian origination locations, and therefore they reflected more linguistic diversity. This may explain Burusho in North India.