Gene Expression

The politics of genetic history in India

A reader pointed me to an article, Aryan-Dravidian divide a myth: Study. Some of the authors of the paper I reviewed today (actually, I wrote the post yesterday and put it in schedule) had some interesting things to say:

The great Indian divide along north-south lines now stands blurred. A pathbreaking study by Harvard and indigenous researchers on ancestral Indian populations says there is a genetic relationship between all Indians and more importantly, the hitherto believed ”fact” that Aryans and Dravidians signify the ancestry of north and south Indians might after all, be a myth.

”This paper rewrites history… there is no north-south divide,” Lalji Singh, former director of the Centre for Cellular and Molecular Biology (CCMB) and a co-author of the study, said at a press conference here on Thursday.

Senior CCMB scientist Kumarasamy Thangarajan said there was no truth to the Aryan-Dravidian theory as they came hundreds or thousands of years after the ancestral north and south Indians had settled in India.

The study analysed 500,000 genetic markers across the genomes of 132 individuals from 25 diverse groups from 13 states. All the individuals were from six-language families and traditionally ”upper” and ”lower” castes and tribal groups. ”The genetics proves that castes grew directly out of tribe-like organizations during the formation of the Indian society,” the study said. Thangarajan noted that it was impossible to distinguish between castes and tribes since their genetics proved they were not systematically different.

”The initial settlement took place 65,000 years ago in the Andamans and in ancient south India around the same time, which led to population growth in this part,” said Thangarajan. He added, ”At a later stage, 40,000 years ago, the ancient north Indians emerged which in turn led to rise in numbers here. But at some point of time, the ancient north and the ancient south mixed, giving birth to a different set of population. And that is the population which exists now and there is a genetic relationship between the population within India.”

The researchers, who are now keen on exploring whether Eurasians descended from ANI, find in their study that ANIs are related to western Eurasians, while the ASIs do not share any similarity with any other population across the world. However, researchers said there was no scientific proof of whether Indians went to Europe first or the other way round.

To understand some of these assertions you have to know that in India there are Creationist-like movements driven by nationalist and Hindu fundamentalist ideologies.

There’s been a lot of debate for decades in India about the Aryan Invasion Theory, which posits that Aryans, generally described as light-skinned northerners, overran the Indus Valley Civilization and subjugated the local peoples. Some Indian groups actually adhered to this, but overall the trend has been sharply against it because white nationalists were big proponents of it, and used it to suggest that the peoples of India are mongrelized degenerates who received the gift of civilization from racially superior Europeans. Today many Indians espouse an Out of India theory. I don’t really agree with either position. The Out of India theory is almost certainly just plain wrong. The Aryan Invasion Theory is a caricatured fact (in contrast to a stylized fact). But first let me quote something from the paper itself:

Two features of the inferred history are of special interest. First, the ANI and CEU form a clade, and further analysis shows that the Adygei, a Caucasian group, are an outgroup…Many Indian and European groups speak Indo-European languages, whereas the Adygei speak a Northwest Caucasian language. It is tempting to assume that the population ancestral to ANI and CEU spoke ‘Proto-Indo-European’, which has been reconstructed as ancestral to both Sanskrit and European languages, although we cannot be certain without a date for ANI-ASI mixture.

This is from the paper that these authors are listed on, but probably written by David Reich. They seem to be going in opposite directions here. I actually think that this section would best be left to the supplements, and other sections of this paper emphasize the likely complexity of the ANI-ASI mixture process. But in the quotes in the media above the other authors seem to be leading you to totally different conclusions from this, instead of leaning toward ANI being Proto-Indo-European, they deny that it is. Instead of demurring on a specific date, they clearly believe that ANI-ASI admixture predates the arrival of Aryans and Dravidians. The second suggests that the authors don’t believe in Out of India, look again at this passage: “Kumarasamy Thangarajan said there was no truth to the Aryan-Dravidian theory as they came hundreds or thousands of years after the ancestral north and south Indians had settled in India.”

The plausibility that the ancestral ANI-Europeans are native to India seems low to me. Dienekes lays out the reasons:

-Suppose postulated ancient Indian PIE speakers had a similar genetic makeup as modern Indians (i.e., a mix of ANI and ASI). Then, the absence of the ASI component outside South Asia cannot be explained.

-If ancient Indian PIE speakers had a purely ANI makeup, then the absence of the ASI component outside South Asia -as in (1)- can be explained. However, this would entail that sharply differentiated populations (ANI and ASI) co-existed in India without mixing for thousands of years; ANI-like PIEs spread from India with their languages; ANI and ASI admixed afterwards. To say that this scenario is not parsimonious would be charitable.

-The only way in which PIE languages may have originated in India would be if they spread without the spread of people. However, before the advent of writing and modern means of transportation and communication, the only way to spread languages was by migration of people.

The authors are correct that this study does not prove the Aryan Invasion Theory (though frankly I believe the first author goes a bit further than I would be willing to go in that very direction!). One would also be correct to suggest that there are ways to salvage the Out of India Theory for the origin of the Indo-European languages, but as Dienekes notes above, they are not genetically parsimonious. Possibility does not equal probability. Additionally, the full range of philological and archaeological data simply do not support the Out of India Theory. In my arguments with South Asian proponents of Out of India Theory I get a sense of arguing with Creationists; they are excellent at bringing up ambiguities and problems in the standard model, but they are blithely unconcerned with the total implausibility of the alternative model that they offer. There is zero chance of them being convinced, they simply need “good enough” arguments to keep you unbalanced.

Now, let me state something clearly: on average an individual from an Indo-Aryan or Dravidian speaking group in South Asia is going to be more closely related genetically in terms of total genome content to anyone in the Indian subcontinent from Indo-Aryan or Dravidian speaking groups than they are to some from outside the Indian subcontinent. Punjabis may bridle at being associated with what they perceive as racially inferior Tamils and Bengalis, but the reality is that they’re closer to these groups than they are to Persians or other West Asian groups (though Punjabis are much closer to Persians than Tamils and Bengalis are, and the Iranian speaking groups of Pakistan are a more ambiguous case). That does not negate significant clines, as well as suggestions of exogenous input (the last point is one “Scythian” descended Northwest Indians can take succor from). Mixed-race Brazilians may form a distinct cluster separate from Portuguese, West Africans and Amerindians, but they are clearly a racial compound of these three groups. The analogy with South Asians is problematic insofar as I think that an overly simple model of admixture may mislead us down the line, but it shows that just because South Asians are a coherent genetic cluster does not mean that they are uniform, or that they all exhibit equal relatedness to other groups.

Finally, I took figure 3 from the paper, and recoded the Indo-European and Dravidian clusters so you can see the effect of language & caste.

i-adbaac8d839b49db8fe42f07d32ff84f-indiadivs.png

Comments

  1. #1 Thorfinn
    September 25, 2009

    WTF?? If the authors had data that the ANI sample really belonged to paleolithic hunter-gatherers, why didn’t they put that in the paper. I don’t have the best bio knowledge here. But nothing that’s in the paper, to my knowledge, can place ANI into 1) Indo-European 2) Paleolithic hunter or 3) Middle Eastern agriculturist without further evidence.

    Nature cautions against the paper being used for political reasons. Yet little in this press release matches what’s in the paper, or anything else I’ve read.

  2. #2 razib
    September 25, 2009

    i think they’re inferring from this:
    Supporting the view of little female ANI ancestry in
    India, it has been reported that mtDNA ‘haplogroup U’ splits into two deep clades44. ‘U2i’ accounts for 77%of copies in India but about 0% in Europe, and ‘U2e’ accounts for 0% of all copies in India but about 10% in Europe. The split is estimated to have occurred about 50,000 years ago, indicating low female gene flow between Europe and India since that time.

    i do think the *historical* and *archaeological* data make it unlikely that ANI is mostly due to a mass migration post-indus valley. that’s not the purview of the paper, but i think the researchers are implicitly pointing to that.

    a bigger issue here is that the coarseness of the model really doesn’t lend itself well to what they’re trying to talk about today. did the ASI mysteriously not inhabit northern india 40,000 years ago? and why are ANI and europeans close anyway, where do they come from? how much of it is mass migration vs. normal gene flow across continuously settled regions?

  3. #3 Matt
    September 25, 2009

    Some Indian groups actually adhered to this, but overall the trend has been sharply against it because white nationalists were big proponents of it, and used it to suggest that the peoples of India are mongrelized degenerates who received the gift of civilization from racially superior Europeans.

    To be honest, Indian with strong nationalistic feeling (a not trivial percentage of the population) probably would be against it anyway and presently are for strictly nationalistic reasons (see the arguments for Paleolithic and Mesolithic continuities as made by various European nationalists).

    I don’t really think the concerns of “White Nationalists”, a strictly US based phenomenon (as opposed to White Supremacism, the idea that Whites are supreme, White Nationalism is the idea that Whites are an undifferentiated nation that should also be a political identity) really had much bearing on this.

  4. #4 razib
    September 25, 2009

    I don’t really think the concerns of “White Nationalists”, a strictly US based phenomenon (as opposed to White Supremacism, the idea that Whites are supreme, White Nationalism is the idea that Whites are an undifferentiated nation that should also be a political identity) really had much bearing on this.

    i was using ‘white nationalist’ in a generic way. in any case, the indian nationalist response is framed in a historic sense against the british 19th century scholarship & research with a colonial bent which posit aryan vs. dravidian differences, with the northern aryans being outsiders whose naturally partook of the proto-indo-european genius, etc.

  5. #5 bioIgnoramus
    September 25, 2009

    “whether Indians went to Europe first or the other way round” sometimes the best response is a guffaw.

  6. #6 megan
    September 25, 2009

    I thought DNA migration history has shown that human dispersal wavesfrom Africa went along the coasts of Meditarranean and Red Sea areas into the Middle East and Persian/Georgia-Caucus Mountain areas and Indian Ocean. So Humans could have remigrated east from Caucus mountainous area as the groups further split and migrated in all directions to represent the Aryans. And the southern Dravidians Indians the older first migrations along the Pacific-Indian ocean routes. Why the big conflict or care.
    Bigots and racists find every reason to support ‘better than’ when it clearly shown the human race is still practically the same genetically and living Neanderthals or Java men would be the only justified delineating and making value judgments based of of that still ethically questionable.

  7. #7 omar
    September 25, 2009

    The analogy with creationists is a very apt one. Its also a good example of how a relatively small group of committed people can muddy a whole big pool; in this case, the hardline hindutva fanatics who believe in all sorts of racist nonsense about the superior pure ultrasmart precociously brilliant (inventors of every useful idea) Hindus of the distant past are really a small minority in India, but their bullshit has colored the discourse well beyond the extreme hindutva fringe. Having said that, I think that Indian academia is not hopeless and a lot of good work will probably get done even while popular discourse is full of nonsensical nationalism and patriotic mythmaking. And worth noting that just as in American academia, the “soft sciences” in India also have a large number of leftwing ideologues who have their own myths to protect and project…

  8. #8 hpushkar
    September 25, 2009

    hey omar u have nicely written but u didn’t mention what myths lefists propogate and why ?

  9. #9 worf
    September 26, 2009

    Razib, I’m just curious what’s your take on the origin of the Dravidians?

  10. #10 Allan
    September 26, 2009

    If I read this article correctly
    the authors claim that both the Indo-Europeans
    and the Dravidians
    migrated into India from elsewhere.

    Although this certainly is true for the IEs
    I don’t see how the evidence contradicts the possibility
    that the Dravidians were the original inhabitants
    of India.

  11. #11 sandy s
    September 26, 2009

    “The observation of R1a* in high frequency for the first time in the literature, as well as analyses using different phylogenetic methods, resolved the controversy of the origin of R1a1* (ANI), supporting its origin in the Indian subcontinent.”

    http://www.nature.com/jhg/journal/v54/n1/full/jhg20082a.html

  12. #12 razib
    September 27, 2009

    sandy, if the above is correct,

    1) ANI and ASI were totally separated in the indian subcontinent

    2) or, there was a selective migration of Y chromosomes only, leaving autosomes behind….

  13. #13 razib
    September 27, 2009

    I thought DNA migration history has shown that human dispersal wavesfrom Africa went along the coasts of Meditarranean and Red Sea areas into the Middle East and Persian/Georgia-Caucus Mountain areas and Indian Ocean. So Humans could have remigrated east from Caucus mountainous area as the groups further split and migrated in all directions to represent the Aryans. And the southern Dravidians Indians the older first migrations along the Pacific-Indian ocean routes. Why the big conflict or care.

    the two-stream model is a hypothesis. my own hunch now is that it’s probably wrong. i suspect there was one stream which split somewhere in northwest india, leading to west and east eurasian clades. then later the west eurasians came back to india (ANI) is what i would bet.

    Razib, I’m just curious what’s your take on the origin of the Dravidians?

    i suspect the bantu expansion is a good analogy. i think the dravidians probably come from the iran-western india region. the survival of the brahui isolate in the hills of balochistan, and the presence of tribal dravidian speaking groups as isolates across north-central india indicate its relative antiquity vis-a-vis indo-european languages. additionally, many philologists claim to see a dravidian lexical substrate in indo-aryan languages. finally, i don’t think that means dravidians came as a human wave, the pygmies speak bantu languages now too. though i wouldn’t be surprised if the dominant signal of ANI had more to do with the dravidian expansion than the indo-aryan one (which may have been a secondary overlay).

    I don’t see how the evidence contradicts the possibility
    that the Dravidians were the original inhabitants
    of India.

    brahui, a dravidian language, is almost in iran. there is circumstantial (though very tentative) arguments that elamite, in khuzistan, was a dravidian-related language. dravidian languages may very well be indigenous to south asia (dating back to the last glacial maximum), but i suspect if they are (which is a non-trivial possibility) then they are indigenous to the northwest regions. i.e., the indus valley civilization. by analogy, consider that quechua in the peruvian highlands actually spread much farther after the spanish conquest, because the spaniards had better communication and organization which allowed the dominant local language to spread.

    the main issue with an out-of-india thesis though is the lack of ASI elsewhere. this is not totally unexpected, mtDNA studies have long shown a lot of native indian lineages, which also pop up elsewhere in the case of gypsies.

  14. #14 worf
    September 28, 2009

    i wouldn’t be surprised if the dominant signal of ANI had more to do with the dravidian expansion than the indo-aryan one (which may have been a secondary overlay)

    So that means the ancient dravidians are ANI or originally ANI before being merged with the ASI to become known as today’s dravidians?

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