New Genetic Findings from India

From Elise Kerndocuff of Berkeley and a bunch of others. All of this is based on modern populations, with a sample of more than 2,700 genomes from across the subcontinent:

1. As with previous studies, the authors find that people in India divide roughly into two groups, known as North Indian and South Indian.
2. People in India derive 1-2% of their genes from Neanderthals or Denisovans.
3. Most people in India descend mainly from a single migration out of Africa that took place roughly 55,000 years ago; only 0-3% of genes might descend from an earlier migration of Homo sapiens sapiens out of Africa that the authors date to about 74,000 years ago. (This is important for other debates but not so important about the population of India; basically, there is an archaeological problem because genetic studies keep finding that Europeans and Asians mostly descent from people who left African 55,000 to 60,000 years ago, but there were Homo sapiens sapiens in Eurasia a lot earlier than that.)
4. Essentially all people in India have genes that descend from Iranian farmers who migrated to India in the Neolithic; to get a sample of south Asian hunter-gatherers without Iranian mixture the authors used Andaman Islanders. Look at the graph at the top and you see that in North India, Iranian farmer (Sarazm) is the largest component, at about 47%. This is what you would expect; farmers had larger populations than hunter-gatherers and genetically dominated wherever they went. The dominance is less extreme in India than in Europe because hunter-gatherer populations were denser in the tropics, and maybe because Indian hunter-gatherers took up farming faster.
5. Most (but not all) people in India have genes from Bronze Age Steppes invaders. As you would expect, this ancestry is stronger in the north, but it is also present in the south. Most archaeologists think these people brought Indo-European languages and the civilization of the ancient Vedas to India.

The authors, as is proper, present their percentages vaguely, with error bars, and in fact they don't print any numbers at all. But squinting at their graph, I come up with these numbers for the mean points in their ranges.

Like everyone else, modern Indians are a mixture of many different ancient populations, which were in turn mixtures of populations who came before them. There are no pure races, or pure civilizations.