Thursday, March 3, 2016

Work In Process Analyzing Deep South Asian History And South Asian Population Genetics

I've been reading a lot of articles on the history and population genetics of the South Asian caste system, and have bookmarked them, but it is taking time to get to the point where I feel that I have a firm enough command of the material to synthesize that information into a well referenced post here.

The story at the top of the caste pyramid is pretty well understood and is fairly familiar to me (although still more complex than conventional wisdom would suggest), as this is deeply interrelated to the relatively familiar topic of Indo-European and Dravidian linguistic origins.

In the middle, the main story seems to be one of regional variation and of the extent to which geography and caste are more relevant to a particular population's genetic makeup.  This story is less familiar, but still seems amenable to an analysis not unlike that done at the top of the pyramid.

But, I'm particularly intrigued by and still coming to terms with understanding the distinction between middle to lower caste individuals and people who are beneath the main varna structure entirely, which consists of two distinct populations: "untouchables" a.k.a. Dalits a.k.a. Scheduled Castes, on one hand, and "tribal" populations, on the other.

Dipping my toe in so far, the population genetics of the Scheduled Castes seem to be dominated by distinctively South Asian features not found in any other population on earth and properly characterized as indigenous.  This begs the question of how the "otherness" of these castes came to be, with a tentative hypothesis that the Scheduled Castes may have been mostly made up of the descendants of prisoners of war captured in wars between South Asian micro-states when the subcontinent had a balkanized political landscape who were held in a slave-like status at some point.

In contrast, so far, the population genetics of "tribal" populations in India appear to vary greatly from tribe to tribe, are sometimes not dominated by genetic features private to South Asia, and do not always have genetics that reflect their current language suggesting that there have been instances of language shift in tribal populations.

It tentatively appears that many of the tribal populations that have been foragers in historical time periods reverted to that status after having ancestors who were probably food producers who migrated to South Asia from outside the subcontinent at some point during the latter half of the Holocene era.  This is contrary to the conventional wisdom that sees tribal populations as the indigenous hunter-gatherers of India, which is true if one looks only to the historic era, but may not be true when viewed from the sweeping perspective of the entire Holocene era.

As I note, these tentative conclusions are subject to change, undigested, unrefined, and not carefully sourced to the references that support them at this point, as I go through the process of assimilating and making sense of the rather large literature on the subject, not all of which is consistent.  But, this post does provide some work in process update to what I've been looking at and thinking about on that score.

I'd welcome comments on these tentative ideas, pointers to different well supported hypotheses, and sources that address these questions from various disciplinary perspectives.

3 comments:

terryt said...

As far as any comment I might make: I think you are basically correct.

Vijay said...

"Dipping my toe in so far, the population genetics of the Scheduled Castes seem to be dominated by distinctively South Asian features not found in any other population on earth and properly characterized as indigenous. This begs the question of how the "otherness" of these castes came to be, with a tentative hypothesis that the Scheduled Castes may have been mostly made up of the descendants of prisoners of war captured in wars between South Asian micro-states when the subcontinent had a balkanized political landscape who were held in a slave-like status at some point"

Two issues with the above understanding are:

1. There is not considerable genetic variation between the "middle" or other backward classes, and scheduled castes. You can refer to zack azmal or Reich database.

2. The second aspect relates to understanding this as a slave issue. Slaves exist in India, but the SC population have not been slaves. They have lived at the edges of the society (the village) literally and figuratively for several hundred years. I know you are trying to understand this from the US or western perspective, but there is no slave<->SC correlation. In fact, the rulers excluded SC from their armies, and they often existed as hangers-on to armies. The Muslims and the British who have ruled India for 8-9 centuries did not take slaves. Confusingly, the slaves taken by muslim armies often rose in position in society, often becoming kings themselves.

Essentially, the SC population were stranded based on their occupation, and became subalterns to the society as a whole.

The ST population is entirely different, and chose a whole series of occupations, from forages, hunters, forest dwellers, fishermen, or even transients. They are not comparable to SC populations. Tribals often ruled themselves and did not engage in Indian politics for several hundred years. Even now, the tribal issues are freedom and demands to govern themselves.

andrew said...

Thanks for the input.

I agree with your point 1 and to the extent that I implied otherwise, that was unintentional.

I appreciate the insights of your point 2. The puzzle in my mind is how the extreme segregation of SC and higher castes occurred in the absence of a significant population genetic distinction. It would seem like it had to have been something epic, but it isn't easy to come up with a narrative to explain it. What is the conventional wisdom regarding the emergence of SC?

I would also agree with you that SC and ST populations are entirely different from each other, and that ST populations are diverse. ST must have come into being through very different historical processes.