Razib Khan One-stop-shopping for all of my content

June 6, 2018

Genetical observations on caste

Filed under: Caste,Genetics — Razib Khan @ 10:49 pm

One of the more interesting and definite aspects of David Reich’s Who We Are and How We Got Here is on caste. In short, it looks like most Indian jatis have been genetically endogamous for ~2,000 years, and, varna groups exhibit some consistent genetic differences.

This is relevant because it makes the social constructionist view rather untenable. The genetic distinctiveness of jati groups is very hard to deny, it jumps out of the data. The assertions about varna are fuzzier. But, on the whole Brahmins across South Asia have the most ancestry from ancient “steppe” groups, while Dalits across South Asia have the least. Kshatriya is closer to Brahmins. Vaisya has lower fractions of “steppe”. And so on. These varna generalizations aren’t as clear and distinct as jati endogamy. Sudras from Punjab may have as much or more “steppe” than South Indian Brahmins. But the coarse patterns are striking.

As a geneticist, and as an irreligious atheist, a lot of the conversations about “caste” are irrelevant to me. They’re semantical.

You can tell me that true Hinduism doesn’t have caste, that it was “invented” by Westerners. They may not have had caste, but the genetical data is clear that South Asians were endogamous for 2,000 years to an extreme degree. Additionally, the classical caste hierarchy seems to correlate with particular ancestry fractions.

Second, you can say Islam, Sikhism, Jainism, and Buddhism don’t have caste. That they picked it up from Hinduism. Or Indian culture. That’s true. But I think Islam, Sikhism, Jainism, and Buddhism are all made up, just like Hinduism. I don’t care if made up ideologies don’t have caste in their made up religious system. I am curious about the revealed patterns genetically.

I have a pretty big data set of South Asians. Some of them are from the 1000 Genomes. Here is where the 1000 Genomes South Asians were collected:

Gujarati Indians from Houston, Texas
Punjabi from Lahore, Pakistan
Bengali from Dhaka, Bangladesh
Sri Lankan Tamil from the UK
Indian Telugu from the UK

Some of the groups showed a lot of genetic variation, so I split them based on how much “Ancestral North Indian” (ANI) they had. So Gujurati_ANI_1 has more ANI than Gujurati_ANI_2 and so forth.

Here is a tree showing pairwise genetic distances between the groups:

The positioning of some groups near each other is an artifact. Dai from China is an outgroup, as are Iranians and Baloch. So all are pushed near each other.

Treemix with 3 migrations shows similar patterns:

Now let’s do a PCA:

Click the link above and you’ll see Bangladeshis are all shifted toward Dai. The Iranians are at the bottom, but nearest to them are the Baloch. Then the Pathan. Then Punjabi_ANI_1.

Let’s zoom in on the South Asian groups.

Do you notice something about the Bangladeshis? They don’t have much South Asian ancestry variation. Their variation is all due to East Asian ancestry, which seems to have a west to east gradient (I’m way on the right edge, and my family is from the eastern edge of eastern Bengali).

This is not the case for Punjabis.

As you can see, the Punjabis sampled in Lahore range form almost Pathan to almost South Indian. This totally shocked me. This is a huge range of variation.

Compare to Gujus:

I’m pretty sure there are only a few Gujurati_ANI_4 because the sampling occurred in Houston, TX (Indian gov. stingy about genetic testing/sampling, so usually done in Diaspora). Notice that Gujus, mostly Hindu, have the same genetic variation as Punjabis!

Now let’s compare Dalits to Brahmins.

To my surprise, Chamars from UP are quite like South Indian Dalits (there is some “steppe” admixture you can detect in Chamars, so they’re not identical). South Indian Brahmins have some local admixture.

What’s my point here?

In some of the comments, there was talk about how Bengali Muslims have their own form of caste. This seems plausible, though I wouldn’t know personally. I wasn’t raised in Bangladesh. But these data make it clear that there’s almost no caste-like structure in Bangladesh genetically. The variation is almost all due to the mixture with East Asian-like people, and that’s almost certainly due to geography (West Bengalis have this, but to a lesser portion, and people from eastern Bangladesh have more than people from western Bangladesh).

In contrast, when you look at the 1000 Genomes Telugu or Tamil sample structure jumps out. First, there are a small number of Brahmins. But there is also a large group which is clearly scheduled caste. Looking at Gujuratis, they are very diverse. The Patels probably anchor the Sudra/ middle-class component dominant in the region.

Punjab looks like the Indian groups, not Bangladesh. I have no idea about Pakistani caste or class dynamics, but the genetics makes it look like the social structure of Hindus. In contrast, Bangladesh looks like a non-South Asian population, with most of the variation being due to geography and proximity to a very different group (Tibeto-Burmans).

I don’t think Bengalis are more punctilious Muslims than Punjabis. I think the social landscape of Bengal emerged out of a frontier expansion which destablized the default Indian caste structures that undergired most societies. In Pakistan Islamicization didn’t perturb the underlying Indianness of Punjabis.

July 17, 2017

Castes are not just of mind

Filed under: Caste,Human Genetics,India — Razib Khan @ 8:31 pm

Before Nicholas Dirks was a controversial chancellor of UC Berkeley, he was a well regarded historian of South Asia. He wrote Castes of Mind: Colonialism and the Making of Modern India. I read it, along with other books on the topic in the middle 2000s.

Here is Amazon summary from Library Journal:

Is India’s caste system the remnant of ancient India’s social practices or the result of the historical relationship between India and British colonial rule? Dirks (history and anthropology, Columbia Univ.) elects to support the latter view. Adhering to the school of Orientalist thought promulgated by Edward Said and Bernard Cohn, Dirks argues that British colonial control of India for 200 years pivoted on its manipulation of the caste system. He hypothesizes that caste was used to organize India’s diverse social groups for the benefit of British control. His thesis embraces substantial and powerfully argued evidence. It suffers, however, from its restricted focus to mainly southern India and its near polemic and obsessive assertions. Authors with differing views on India’s ethnology suffer near-peremptory dismissal. Nevertheless, this groundbreaking work of interpretation demands a careful scholarly reading and response.

The condensation is too reductive. Dirks does not assert that caste structures (and jati) date to the British period, but the thrust of the book clearly leaves the impression that this particular identity’s formative shape on the modern landscape derives from the colonial experience. The British did not invent caste, but the modern relevance seems to date to the British period.

This is in keeping with a mode of thought flourishing today under the rubric of postcolonialism, with roots back to Edward Said’s Orientalism. As a scholar of literature Said’s historical analysis suffered from the lack of deep knowledge. A cursory reading of Orientalism picks up all sorts of errors of fact. But compared to his heirs Said was actually a paragon of analytical rigor. I say this after reading some contemporary postcolonial works, and going back and re-reading Orientalism.

To not put too fine a point on it postcolonialism is more about a rhetorical posture which aims to destroy what it perceives as Western hegemonic culture. In the process it transforms the modern West into the causal root of almost all social and cultural phenomenon, especially those that are not egalitarian. Anyone with a casual grasp of world history can see this, which basically means very few can, since so few actually care about details of fact.

Castes of Mind is an interesting book, and a denser piece of scholarship than Orientalism. Its perspective is clear, and though it is not without qualification, many people read it to mean that caste was socially constructed by the British.

This seems false. It has become quite evident that even the classical varna categories seem to correlate with genome-wide patterns of relatedness. And the Indian jatis have been endogamous for on the order of two thousand. From The New York Times, In South Asian Social Castes, a Living Lab for Genetic Disease:

The Vysya may have other medical predispositions that have yet to be characterized — as may hundreds of other subpopulations across South Asia, according to a study published in Nature Genetics on Monday. The researchers suspect that many such medical conditions are related to how these groups have stayed genetically separate while living side by side for thousands of years.

This is not really a new finding. It was clear in 2009’s Reconstructing Indian Population History. It’s more clear now in The promise of disease gene discovery in South Asia.

Unfortunately though science is not well known in any depth in the general public. The ascendency of social constructionism is such that a garbled and debased view that “caste was invented by the British” will continue to be the “smart” and fashionable view among many elites.

July 25, 2012

A little food & medicine go a long way

Filed under: Caste,Lower Caste,Prejudice,race — Razib Khan @ 7:45 am

I clicked through on the links to Zack’s post below and was pretty shocked. I know this somewhat, but not having grown up around many Indians (or South Asians generally) I didn’t have a good sense. That being said, a few years ago I stumbled on a book at the local book store, Daughter of the Ganges: A Memoir. The author was an adopted woman of Indian heritage from Spain. Skimming through, her family seems to have been peasant cultivators in Maharashtra. Therefore, I was struck by her photo. She is rather attractive and not “worn down” by the life of extreme subsistence.

This is not to take anything away from Zack’s post, and she obviously does not look like the typical upper caste NRI even to my unsubtle eyes. But a great deal of the physical difference in terms of perception is environmental. Though I do think it is telling that a woman who looks like this could never be a leading lady in a Bollywood film.

Asha Miro


July 2, 2012

What India can teach the world

Filed under: Caste — Razib Khan @ 10:07 pm

Years ago I read that M. K. Gandhi defended caste in the ideal against Western critiques by pointing out that it dampened some of the competitiveness one finds in Western society. I dismissed this defense at the time, but in some ways I am now willing to concede its validity. Over the past few years I have come to the conclusion that we are now entering into a new age of radical inequality. Globalization is a fait accompli, but so is the rise of a new elite. The uplift of the peasant masses will occur, but de facto endogamous ruling castes will also crystallize. India has shown that thousands of years of endogamy and inequality can maintain civilization. This example is India’s gift to the world.


June 7, 2011

Caste is not ancestrally arbitrary

Filed under: Admixture,Caste — Razib Khan @ 5:10 pm

First, thanks to Zack for the opportunity to blog here. More importantly, thanks to Zack for the Harappa Ancestry Project! I've learned a lot from him in terms of the optimal way to go about "genome blogging," and have been able to benefit from his experiences in my own African Ancestry Project. It's really great that in 2011 we don't have to wait for academic researchers to explore the topics which interest us at the intersection of genetics and history.

Prior to being interested in South Asian genetics on such a fine-grained level I had read works such as Nicholas B. Dirks' Castes of Mind. To give you a sense of Dirks' argument, here's the summary from Library Journal:

Is India's caste system the remnant of ancient India's social practices or the result of the historical relationship between India and British colonial rule? Dirks (history and anthropology, Columbia Univ.) elects to support the latter view. Adhering to the school of Orientalist thought promulgated by Edward Said and Bernard Cohn, Dirks argues that British colonial control of India for 200 years pivoted on its manipulation of the caste system. He hypothesizes that caste was used to organize India's diverse social groups for the benefit of British control. His thesis embraces substantial and powerfully argued evidence. It suffers, however, from its restricted focus to mainly southern India and its near polemic and obsessive assertions. Authors with differing views on India's ethnology suffer near-peremptory dismissal....

One of the inferences which people draw from this model, perhaps unfairly, is that the endogamy and biological separation of caste groups is relatively new, and that genetic variation is likely to be arbitrarily distributed across caste groups. The most extreme interpretations almost seem to turn the British into the culture-creators of all that is Indian. In any case, genetics can obviously test the power of this thesis in relation to ancestry.

First up, below I have taken all the HAP samples where N >= 2. I've done some semantic shifting, so that "Tamil Iyer" becomes "Tamil Brahmin." I know that some of you have more information about the samples than is listed in Zack's spreadsheet, but I've been conservative. I will also use the word "community" sometimes instead of "caste" in future posts, because I don't know what the proper word for Syrian Christians or Bihari Muslims would be. But really same difference to me. I want to focus on groups with caste/religious labels intersected with a specific region here. The bar plot below is not going to be a surprise, and you see the clusters in Zack's dendograms, but I thought it would still be useful.

Caste is not genetically arbitrary. To me this strongly falsifies any contention that the endogamous units which we know as castes (or jatis) derive predominantly from the past 200 to 300 years. Tamil Brahmins number in the millions, so it does not seem that they plausible that could have expanded so rapidly from a very small homogeneous founder group two to three centuries ago. Rather, their origins are almost certainly more ancient. Some of the results are also not that surprising. Northwest Indians have the genetic profile you'd expect in comparison to other groups. The Bengali Brahmins consistently have more of an "East Asian" trace than other Brahmin groups, while Tamil Brahmins seem elevated in the "SW Asian" fraction in relation to other Brahmins. Both of these trends I think illustrate the likelihood of some admixture with location populations.

Now let's look within regions a bit. I'll divide South Asia into four quadrants. The classification will be self evident from the bar plots.

I'm the third to last Bengali, while the last two are are my parents. My parents are not related, and from opposite ends of Comilla east of the Padma. My mother is the last bar plot, and from a family with attested Middle Eastern ancestry (non-South Asian focused ADMIXTURE runs tend to bring the small, but non-trivial, element out more clearly). I believe that that is what is elevating her "SW Asian" fraction. It is notable that the two other individuals from eastern India who show this balance between "SW Asian" and "European" are also of Muslim background. I doubt that that is coincidental. Though South Asian Muslims are overwhelmingly indigenous, they do seem to have some outside admixture since the arrival of Arabs, Persians, and Turks, to the subcontinent. The most obvious marker of this to me isn't the elevation of "SW Asian," but the common presence of African ancestry among Pakistani Muslims. This certainly is due to the arrival of Africans and people of part African origin in the retinues of Indo-Islamic rulers.

Aside from this it seems more clear to me now that like in South India the Brahmins of the east are also relatively new and intrusive. All show an elevation of "European," though the trace of "East Asian" suggests admixture. That probably indicates their arrival after the absorption of the Mundari populations, and perhaps Tibeto-Burmans, into the substrate of eastern India.

I find nothing important to say here aside from the fact that we need a lot more samples for UP! The UP Kayastha indicates that there's a fair amount of variation here which is not being sampled.

We are obviously rich in samples from South India. One interesting aspect is the bias toward "SW Asian" as opposed to "European" among non-Brahmins, especially what I think are termed "Forward Castes" (e.g., Reddy). The proportions are low, but consistent. This is the inverse of what we see among non-Brahmins in East India. I am liable to dismiss the the East Asian admixture among many South Indians, especially non-Brahmins, as noise, but it may be signatures of absorbed Mundari substrate. Who knows? The Kerala Christian samples have the most "SW Asian." We need better references from other non-Brahmin non-tribal/Dalit castes in Kerala (a Nair is coming up), but I wonder if this validates the idea of some Semitic admixture of yore among Nasranis (or, perhaps just as likely long term trade and marriage connections over the centuries).

Now let's just look at South Indian Brahmins.

Very similar, huh?

Finally, the last cluster in western India:

Not much to go on, though I've been told that several of the Gujaratis are Patels.

Overall I think we can reject a strong recent post-colonial social construction of caste as a plausible model going by genetics. What replaces it? There probably won't be a neat model. But hopefully as HAP expands it can fill in some of the gaps. The 1000 Genomes Project will be releasing Assamese Ahom, Bengali Kayasthas, Marathas from Maharashtra, and Punjabis from Lahore, this year.

April 30, 2011

Pride in self, and what self is

Filed under: Caste,Culture,Identity — Razib Khan @ 10:48 pm

In the post below I was clearly poking fun at people who I believe are unseemly in their espousal of group identity and pride in that identity. I did not though imply that all such pride and affinity is unseemly. There are two issues. One is endogenous, and one is exogenous. The endogenous one is of values. People exhibit a range of natural or learned disposition in terms of their individualism. I for example have minimal interest in group affinity in a deep and fundamental sense, as I think so little of the human race as a whole. I’d rather focus on improving myself than spending a great deal of time exploring and reflecting my “heritage” because it is my heritage. For me my grandparents were an accident of birth. Other people can take a different perspective because they are different.

The second issue is exogenous, and that is one of context. This is more intelligible in terms of religion. Below Zack expressed the wish that a co-religionist should not appeal to God in making an argument. This is a matter of public reason. I don’t believe in God, so not only does an appeal to a non-existent primitive superstition not move me, but it might distract me. It is also unseemly that an individual interpose their primitive superstition into a serious argument. On the other hand if the argument is aimed at those whom you can be assured are theists then it seems eminently reasonable to use language which nods to one’s theistic presuppositions. More narrowly, if your audience consists of Christians, speak of Jesus. If they consist of Muslims, speak of Muhammad and Allah. One of the main issues I have with Islam is that Muslims are not always trained in the West that the religious chauvinism that they take for granted in their barbaric cultures of origin are not acceptable in the public forum. The only religionists who speak about their faith in specific and effusive terms in the United States as Muslims are evangelical Christians, and their mode of interposing religion into the public discussion has been a major source of political and social conflict.

I think the lesson when it comes to ethnic or community pride is the same. Within the ethnos or community pride can be healthy and taken in stride. But in a more mixed gathering it often is seen to be farcical posturing. Additionally many individualists like myself often stereotype the sorts who prattle on about their group identity as losers who have no individual excellence to appeal to. No offense, but my experience is that the Jews who talk constantly about the accomplishments of their nation in domains such as Nobel Prize awards are the Jews who are the least likely of all to ever attain the level of achievement worthy of any recognition.

True excellence is understated.

April 27, 2011

Caste-dropping, for the rest of us

Filed under: Caste — Razib Khan @ 10:48 am

Reader Barani says below:

Sikhs do have caste.

All the Sikh Gurus were Khatris and married only other Khatris.

At some point, enough Jats converted to Sikhism so that they started taking over from Khatris.

There are also untouchable Mazbhi Sikhs

Each caste has its own Gurudwara

Lobana ranks below Jat and Khatri.

Nawaz Sharif was a Lobana

The clarification is important. I knew the word Jatt because Jatts are really obsessed with being Jatt quite often. I know the word Khatri because offhand a friend mentioned his family was Khatri years ago. Had no familiarity with the word Mazbhi or Lobana before basically now, let alone what the terms were supposed to connote. Two points:

1) Please don’t use brown caste words without giving a casual identification and relevance. A lot of us aren’t familiar with that sort of stuff and what you are trying to get at.

2) Also, please keep in mind that in the West everyone is a “sand nigger.” Keep some perspective on how important this is to anyone abroad.

January 31, 2011

Where are the Brahmins?

Filed under: Caste — Razib Khan @ 10:35 am

On related note, Business Class Rises in Ashes of Caste System. I have a friend who is of the Nadar caste mentioned. His father is a chemist in San Diego. Unfortunately for him he’s very inbred due to marriage customs in his family’s community, something he wants to change in the next generation.

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