I am not a scientist, and this is not a science blog. But the just-published study in Nature may have interesting implications for some important legal and political debates around caste. India, the study claims, has been under-represented in 'genome-wide surveys of human variations', so this is apparently one of the first of its kind. Before we look at its implications, here is a summary of the results:
The researchers showed that most Indian populations are genetic admixtures of two ancient, genetically divergent groups, which each contributed around 40-60% of the DNA to most present-day populations. One ancestral lineage — which is genetically similar to Middle Eastern, Central Asian and European populations — was higher in upper-caste individuals and speakers of Indo-European languages such as Hindi, the researchers found. The other lineage was not close to any group outside the subcontinent, and was most common in people indigenous to the Andaman Islands, a remote archipelago in the Bay of Bengal.
The researchers also found that Indian populations were much more highly subdivided than European populations. But whereas European ancestry is mostly carved up by geography, Indian segregation was driven largely by caste. "There are populations that have lived in the same town and same village for thousands of years without exchanging genes," says Reich.
An important biomedical implication of the study is that 'there will be an excess of recessive diseases in India'. But socially, this study challenges the following theses on the origins and nature of the caste system in India:
1. Caste is a modern, colonial invention:
This genetic evidence refutes the claim that the Indian caste structure was a modern invention of British colonialism, the authors say. "This idea that caste is thousands of years old is a big deal," says Nicole Boivin, an archaeologist who studies South Asian prehistory at the University of Oxford, UK. "To say that endogamy goes back so far, and that genetics shows it, is going to be controversial to many anthropologists."
2. Indigenous origins of the 'Indo-Aryans':
The theory, especially popular with some RSS ideologues like Golwalkar, that Indo-Aryans originated in India and did not come from elsewhere has become even more untenable. Assuming that the RSS's 'Indo-Aryans' are the same as what the study calls 'Ancestral North Indians', their Middle-Eastern/Central-Asian/European origins may be inferred from this finding:
...the 'Ancestral North Indians' (ANI), is genetically close to Middle Easterners, Central Asians, and Europeans, whereas the other, the 'Ancestral South Indians' (ASI), is as distinct from ANI and East Asians as they are from each other. By introducing methods that can estimate ancestry without accurate ancestral populations, we show that ANI ancestry ranges from 39–71% in most Indian groups, and is higher in traditionally upper caste and Indo-European speakers.
Of course, this finding does not make the ANI's any less 'Indian'. It only raises problems for those who sustain the 'pitribhumi - punyabhumi' thesis of exclusionary nationalism by relying on the indigenous origin theory.
3. Is caste race?
Why does it matter? Both caste and race are human constructs, but because of their association with endogamy, may have implications for human genetic make-up. Both have been used to exclude and discriminate. Does it matter what we call such exclusion?
For lawyers, it does. International law and legal institutions have developed to deal with racism. Caste, seen as a one-region problem, has not received similar attention. The issue became controversial in 2001, when the International Conference on Racism in Durban took place. Many dalit groups insisted that casteism was a form of racism; while the government, in keeping with its approach to all international monitoring of human rights, strongly refuted the claim. If caste was indeed race, India would be pulled up by the international institutions that deal with racism. Much academic time has been spent on the issue since the conference. Under the International Convention on Racism, descent and ethnic origin are constituent elements of 'race' One wonders what the implications of the research will be on this debate.