Tibet

MBE has a couple of new articles on altitude adaptation in Tibetans. One talks about a particular mutation in EGLN1, a key gene in the response to hypoxia. The mutation, around 0.5% in most other populations, has soared to 70% frequency in Tibetans. They estimate that this selection began about 8000 years ago, while another Tibetan hypoxia defense (there are several) is a good deal older, something like 18,000 year old. The second paper, with many of the same authors, concludes that the Tibetan plateau was originally settled as far back as 30,000 years ago, while a fraction related to the Han was added to the Tibetan mix in the early Neolithic. They think that the people of the earlier, pre-agricultural phase originally lived in some of the lower parts of Tibet ( < 3000 meters), while colonization of the higher parts of Tibet happened after the domestication of the yak and barley. Colonization of higher altitudes led to increased selection for resistance to hypoxia.

This scenario makes a lot more sense than Rasmus Nielsen's notion that Tibetans adapted to high altitude in less than 3,000 years, which I never believed. Reminds me of the line in Dirty Harry where Callahan says that anybody could tell that he hadn’t beaten up Scorpio: “Because he looks too damn good, that’s how!”

The Tibetans deal with high altitude much more effectively than the Amerindians of the Altiplano. You have to think that they’ve lived there longer, been exposed to those selective pressures longer – and that’s quite feasible. Anatomically modern humans have been in Asia much longer than in the Americas, and it’s even possible that they picked up some adaptive altitude-adaptation genes from archaic humans that had been there for hundreds of thousands of years.

There’s another interesting point: the hunter-gatherers of Tibet appear to account for a lot of Tibetan ancestry, probably most of it, rather than than being almost entirely replaced by a wave of neolithic agriculturalists, which is the more common pattern. They had a trump card – altitude adaptation. A story like that which has left Bolivia mostly Amerindian.

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36 Responses to Tibet

  1. spandrell says:

    I’ve met Tibetans and they do look (and behave) quite distinct from the Han.

    Btw it seems the British NHS is catching up with ya:
    http://www.guardian.co.uk/society/2013/may/07/antibiotics-cure-back-pain-patients

  2. anon says:

    Stop with this nonsense. The only difference between human groups is cultural.

  3. ironrailsironweights says:

    The Tibetans deal with high altitude much more effectively than the Amerindians of the Altiplano.

    In what respect(s)?

    Peter

  4. g2-337af867fe9cd20258bdbc586fbefd0d says:

    China is settling Tibet with Han colonists. How do they manage without air?

    • Toddy Cat says:

      Not particularly well, from what I’ve heard. I believe that Han colonization is mostly concentrated at (relatively) lower altitudes.

    • Alexander M. Kim says:

      The permanent settlers do prefer the relatively lower and wetter valleys. The thing to realize is that the PRC’s Tibetan Autonomous Region (Xizang), ethnic/historical Tibet, and the Tibetan Plateau are not neatly coterminous, and that fairly significant minority Han presence in portions of the latter two (not to mention Mongols, Hui, etc.) precedes 1949. The Kham and Amdo regions are messily divided between Qinghai, western Sichuan, southwestern Gansu, northwestern Yunnan, and parts of eastern Xizang (which otherwise corresponds fairly well to Ü-Tsang, or Central Tibet). Gansu (91%) and Sichuan (95%) are, province-wide, easily majority Han and have long been peripheral portions of China Proper (which is not to deny that Han get scarcer the further west and higher up you go … just look at the demographics of the assorted Tibetan Autonomous Prefectures and Counties).

      Qinghai’s an especially interesting case – it was first subjected to major Han influx under the Qing (who administered it as a superintendency of Gansu), a policy resumed by the PRC, and is today 54% Han. Average elevation over 3000 m, and Han have a majority 65% share of Haixi Mongol and Tibetan Autonomous Prefecture and a 37% plurality in Haibei Tibetan Autonomous Prefecture, both around that figure. (Denver, by contrast, is at 1600 m).

      I haven’t yet found a good breakdown of Han colonists who were relocated to Tibet (in any sense) in the PRC era, but it seems that many of them originated in Sichuan, which – while this was undoubtedly the outcome of proximity and population density more than conscious design – leaves me curious about long-term retention rate by provincial origin. Han intermarriage with Tibetans is historically attested from the interface of the two worlds, and it would be interesting to examine frequencies of altitude-adaptation alleles amongst Sichuan and Gansu Han, who were perhaps better suited on the onset than coastal Han for enlistment in high-elevation projects of demographic reordering.

      By the way:

      “Xizang [TAR] keeps the world record in the height of the upper limits of cold resistant plants such as highland barley, rape, wheat, potatoes and so forth. For example, the land sown with highland barley in Saga County can be up to 4,750 m above sea level, 650 m higher than in the Andes.” Upper altitudinal limits also given for maize (3,200 m), tea (2,500 m), and rice (2250 m).

      • g2-337af867fe9cd20258bdbc586fbefd0d says:

        Gansu and Sichuan are far from Tibet and the mountains. I think that intermarriage is not frequent as of now.

      • Pincher Martin says:

        “Gansu and Sichuan are far from Tibet and the mountains.”

        Both provinces are heavily mountainous – Gansu in the south and Sichuan all around its basin. Both provinces have autonomous prefectures for Tibetans. And both were once part of the ancient Tibetan empire that invaded the Tang dynasty in the 7th century, at one point even capturing its capital city of Chang’an.

        Alexander Kim’s remarks are highly informed and accurate. You should listen to him.

      • Pincher Martin says:

        “And both were once part of the ancient Tibetan empire that invaded the Tang dynasty in the 7th century, at one point even capturing its capital city of Chang’an.”

        Just to clarify, I mean that some parts of these two provinces once belonged to the Tibetan empire. I don’t want to suggest that’s how Tibetan peoples ended up in those areas. The presence of Tibetan-language speakers in the mountainous regions of those provinces almost certainly predates the Tibetan empire by many, many years, and has more to do with their geographical and ecological contiguity with Tibet than it does with any political event.

  5. Matt says:

    Hmm. So http://mbe.oxfordjournals.org/content/early/2013/05/10/molbev.mst090.abstract and http://mbe.oxfordjournals.org/content/early/2013/05/16/molbev.mst093.short?rss=1

    the hunter-gatherers of Tibet appear to account for a lot of Tibetan ancestry, probably most of it, rather than than being almost entirely replaced by a wave of neolithic agriculturalists, which is the more common pattern

    The Tibetan genome samples collected by Simonson have been analysed in one of the internet genographic projects (Harappa), and came out as a not too unconventional mix of North East Asian components (around 80%) which are highest frequency in Japan and North China with some fairly minor contributions of components which are highest frequency in Siberian populations. (10%) and the rest being spread between Indian and other trace components.

    http://www.harappadna.org/2012/03/simonson-tibet-dataset/
    https://docs.google.com/a/zackvision.com/spreadsheet/ccc?key=0AuW3R0Ys-P4HdDhib1M5OE1wWENNb2haUFFWZzNBMEE#gid=0

    The genetic divergence of Tibetans overall seems like not hugely increased compared to the Japanese-Chinese divergence (it’s like double the size and possibly in a European-like direction), e.g. http://www.sciencemag.org/content/suppl/2010/05/11/science.1189406.DC1/Simonson-SOM.pdf

    Whether this would turn out to be because Tibetans are unique in a global context, so are not well represented in a cross Asian study until high levels of K or PCA dimensions are achieved or they are truly not that remarkable in terms of most of their genome, has interesting implications if we model them as a recent admixture between a majority and a minority of 18000 – 30000 year diverged populations (in terms of the how divergent populations with this length of time divergence would be expected to be).

    ….

    Not exactly on topic, but Asia, agriculture, so anyone with any expertise have any thoughts on this study result – http://phys.org/news/2013-05-agriculture-china-years.html#inlRlv “The first evidence of agriculture appears in the archaeological record some 10,000 years ago. But the skills needed to cultivate and harvest crops weren’t learned overnight. Scientists have traced these roots back to 23,000-year-old tools used to grind seeds, found mostly in the Middle East.
    Now, research lead by Li Liu, a professor of Chinese archaeology at Stanford, reveals that the same types of tools were used to process seeds and tubers in northern China, setting China’s agricultural clock back about 12,000 years and putting it on par with activity in the Middle East. Liu believes that the practices evolved independently, possibly as a global response to a changing climate.”

  6. pdevans says:

    Is the incidence of cataracts different between the Han and the indigenous population?
    30K years seems like long enough for a selection against UV light damage.
    A genetic difference in lens crystallins would be ….illuminating… with regards to disease progression.

  7. Steve Sailer says:

    Tibetan Sherpas are world famous high altitude mountain climbers (e.g., Tensing Norgay, 2nd man to the top of Everest). The Andes go up to 23,000 feet, but I’ve never heard of the Andean equivalent of the Sherpas.

    • misdreavus says:

      Sherpas are a separate ethnic group from Tibetans, although both speak Tibeto-Burman languages.

      • Toddy Cat says:

        The Inca had reached the summits of most of the mountains in their empire, and even built cities at altitudes of 12,500 ft, but I can’t find any real analogs to the Sherpas. Here’s a link concerning high-altitude Inca settlements.

        http://news.nationalgeographic.com/news/2002/03/0314_0318_vilcabamba.html

      • Greg Pandatshang says:

        Whether or not Sherpas are a “separate ethnic group” is an exercise in arbitrary line-drawing, but they are clearly closely related to the Tibetans. Their language is not just “Tibeto-Burman” but is a dialect of Tibetan, fairly close to the prestige standard. In short, Sherpas are Tibetan as far as matters for this discussion. Perhaps they are intermixed with indigenous mountain groups, but those groups would likely have comparable adaptations.

      • misdreavus says:

        You might make a case there for genetics, but Sherpa belongs firmly outside U-Tsang cluster which includes the Lhasa dialect. The two are not mutually intelligible.

        My notion that Sherpas were a different ethnic group came from a book on Asian ethnology. I might be wrong. They don’t seem to identify as Tibetans.

        But you are right, all this is hair splitting.

  8. Do Tibetans have the equivalent of coca leaves? Do they need to? Andeans seem to.

    • bruce says:

      I wonder if a gene-enhanced panting Tibetan gets a thrill from yoga hyperventilation the rest of us need Bolivian marching powder to match.

      The Himalayas have blocked off a huge trade route, forever. Bolivia, not. Ethiopean highlands, sort of. There’s got to be a big difference in population variation with a big difference in available population size.

  9. Soxy says:

    I think sherpas are mostly nepalese.

    • Greg Pandatshang says:

      Nowadays, the word “Sherpa” may have been adapted into a job description for a mountain-climbing assistant, so that it now has two meanings: in addition to being a job description, it’s an ethnic group (a bit like the word Gurkha, thus). The word “Nepalese” adds further potential confusion. Do we mean Nepalese citizenship, or one of the dominant, relatively lowlandish Nepali ethnic groups? I think most ethnic Sherpas are Nepalese citizens, and lucky for them, although certainly some Sherpas are Chinese citizens, probably some are Indian citizens, and maybe a few are Bhutanese citizens. Nowadays, skilled mountain-climbing assistants might often be from other Nepalese ethnic groups, I don’t know. But certainly the most famous mountain-climbing Sherpa was Tenzing Norgay, who climbed with Edmund Hilary, and he has a very Tibetan-sounding name.
      Incidentally, “Sharpa” means “easterner” in standard Tibetan. The Sherpas, per oral tradition, are originally Khampas from eastern Tibet, although they have adopted a non-Kham dialect. This is not an isolated case: the cultural toolkit of the Tibetans appears to have allowed them many opportunities in the last 1,000 years to intrude into tribal lands in the Himalayas, although the lines can be blurry, especially at first glance, because the people they were intruding upon were their genetic and linguistic cousins. The intrusions seem to have been primarily private or small-scale rather than the initiative of major Tibetan political powers. The most prominent example is Bhutan, where Tibetan dialect-speaking minority forms a religio-political élite with a non-Tibetan-speaking majority that you never hear about.

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  11. The fourth doorman of the apocalypse says:

    Good thing you didn’t go to Harvard. You would probably be in trouble now.

    • misdreavus says:

      Bunch of goddamn morons.

      High IQ or not, being habitually wrong about things that truly matter is a sign of stupidity.

      • Janon says:

        A lot of the signers appear to be K-school M.P.A. students. The K-school M.P.A. program and Ed School are two weak spots for admission if one wants a “real” Harvard degree but isn’t competitive for admission to the College, graduate school in the Faculty of Arts and Sciences, law school, medical school, or business school. Some of the K-school economists, on the other hand, do rigorous work and may expect it of their Ph.D. candidates. Also, a lot of the signatories appear to be Hispanic. This petition may have circulated among a Hispanic student email list. Their response may be more a matter of emotion than logic.

      • misdreavus says:

        Oh, you seem to think students in the humanities or even physical sciences espouse political opinions that are even more astute? I talked to more than a few. I doubt it.

  12. dave chamberlin says:

    Tibetans seem awfully peaceful for being mostly descended from hunter gatherers. But then there are exceptions to every rule. Typically hunter gatherers fought tooth and nail for their very large required teritory, just like all the other carnivores (yes they were omnivores but that meat was damned important). But tibetans didn’t have to fight so hard. Encroachers didn’t flourish. Where the tire meets the road in keeping out non adapted high altitude populations from the Himalayas or the Andes is mothers can’t bring babies to term. Pregnant women evolved to abort babies in hard times and the body doesn’t know the difference between high altitude and hard times.

    • gcochran9 says:

      Dave, everyone is descended from hunter-gatherers. Agriculture has been around fro a quite a while in Tibet.

    • Pincher Martin says:

      Tibetans are not a peaceful people. They’re a mean, hard bunch. Until recently, they were governed by a theocratic feudalism that was the result of different Buddhist sects continuously vying for supremacy over many centuries. So even if “encroachers” haven’t been a constant threat to the heart of Tibet, that didn’t prevent Tibetans from going to war with each other. Tibetan monks had no trouble with, and saw no contradiction in, dropping their sutras on meditation to pick up clubs and bash in the heads of a few monks from a rival monastery.

      On the southeast margins of Tibet, in the traditional region of Kham, the Tibetans there are reputed to be among the fiercest people in all of China. They’re the equivalent of gun-toting cowboys in the American Wild West.

    • IC says:

      Dave, you are a perfect product of Western fair-balanced media (Western propaganda machine with anti-china agenda)

      • Toddy Cat says:

        I remember back in ’59, when the Tibetans rose up against the ChiComs, the Khams fought like maniacs, as did a lot of other Tibetans. I have no idea what Tibetans are like now, but they certainly were no pacifists fifty years ago.

  13. Greg Pandatshang says:

    Seem peaceful? The Dalai Lama seems peaceful, but he is a bit of an outlier (and arguably a Mongol genetically). In China, Tibetans have a reputation for rowdiness. I can’t see that that’s far off the mark, especially as concerns the eastern Tibetans (obviously they would be more likely to interact with Chinese people), who are passionately tribal, in contrast to their countrymen from the manorial-agricultural west. The imperial British classified the eastern Tibetan Khampas as a “martial race”. In tribal Tibet, there was a strong culture of feuds and revenge killing, which I don’t think was unknown in the agricultural areas, either.

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