Yesterday, I went through the chapter on India in David Reich’s wave-making book Who We Are and How We Got Here: Ancient DNA and the new science of the human past. I’m listing a few thoughts here.
Until now, archeology and anthropology were the key disciplines that helped us decode our past. But now, DNA studies have matured and are adding new, explosive insights. And these studies have a lot to say about ancestry of Indians.
First, Indian bigots of all garden varieties will find the conclusion of the chapter on India deeply disturbing. What it essentially says is that nearly all Indians have significant ‘outsider’ ancestry. None of us are exclusively indigenous.
.. We found that West Eurasian-related mixture in India ranges from as low as 20 percent to as high as 80 percent.. No group is unaffected by mixing, neither the highest nor the lowest caste, including the non-Hindu tribal populations living outside the caste system.
There’s large amount of Iranian-related ancestry in all of us, regardless of whether you are from the north or from the south.
Second, this mixing of ancestry happened in the last 4000 years. Which means, the people who lived on this land 4000 years back were completely different from the people who live here today.
Subsequently, the caste system and resulting endogamy meant that Indians were never truly a single large population like the Han Chinese. Instead, India is composed of a large number of small populations.
People tend to think of India, with its more than 1.3 billion people, as having a tremendously large population, and indeed many Indians as well as foreigners see it that way. But genetically, this is an incorrect way to view the situation. The Han Chinese are truly a large population. They have been mixing freely for thousands of years. In contrast, there are few if any Indian groups that are demographically very large, and the degree of genetic differentiation among Indian jaati groups living side by side in the same village is typically two to three times higher than the genetic differentiation between northern and southern Europeans.
This sustained endogamy over thousands of years makes Indians more susceptible to rare disease-causing mutations. Just one more reason for why endogamy propagated through caste sucks.
So next time someone tells you to ‘go back where you came from’, hold their hand and ask them to join you for a trip to West Eurasia.
And if you’re interested, we have a podcast episode on this chapter on Puliyabaazi.