Geneticists say Chinese and Tibetans were once one. The news appears to be welcome to neither side

TO DREAMERS in the West, Tibet is a Shangri-La despoiled by Chinese ruthlessness and rapacity. To China's rulers it is a backward kind of place whose former serfs, “liberated” by the Communist army, have repaid the favour with ingratitude and even outright “splittism”. But to excited scientists, Tibet is the site of possibly the fastest case of human evolution through natural selection in the history of mankind.

The Tibetan plateau has an altitude of 4,000 metres (13,000 feet or two-and-a-half miles), where the air has two-fifths less oxygen than at sea level. When China's dominant Han come to Tibet, they succumb to altitude sickness and suffer lower birth rates and higher child mortality than locals.

A study led by the Beijing Genomics Institute and published in Science earlier this month identified a particular genetic mutation as a key to Tibetans' high-altitude adaptability. Studying contemporary Tibetan and Han populations, the researchers claim that the two ethnic groups were once a single population, divided, they guess, 2,750 years ago, when one lot of splittists—who became Tibetans—moved to the plateau.

There, they say, the mutation that existed in under a tenth of the population spread to nearly nine-tenths—because those with it survived far better than those without. The particular gene seems to code for a protein involved in making red blood cells and regulating the body's aerobic and anaerobic metabolism.

So much for the science. Now for the politics. Genetics is a minefield given Tibetans' aspirations to govern themselves. Not everybody is happy with the notion that Tibetans were Chinese until 2,750 years ago. For a start, says Robbie Barnett, a prominent scholar and defender of Tibetan culture at Columbia University, most archaeologists agree that the plateau has been settled for much longer than that. And what's to say the “Han” were not descended from the “Tibetans”, rather than the other way around? What would be the correct communist term for describing that, Mr Barnett wonders: Meta-Über-Reverse Splittism, perhaps?

Others respond that a plateau culture predating the migration is in fact compatible with the science. Genetic change can overlay archaeological or cultural continuity. For Mr Barnett to dismiss the connections between early Han and Tibetans, says another scholar, is “just misguided Tibetan primordialism”.

When it comes to the contentious issue of China's political and territorial claims on Tibet, the basis of its current repression rests not on a sense of common heritage or shared ancestors but on a sense of legitimacy based on territories historically controlled by the Qing dynasty. They were Manchus who ruled China from the mid-17th to early 20th centuries and expanded the country's borders. The irony is that while the communists cling to the frontiers of the Qing empire, their official history condemns the Qing as feudal, foreign, imperialist and usurping.

Holding to the Qing frontiers calls for some curious historical nomenclature. Because ethnic Mongolians live within China's borders today, Genghis Khan is given star billing as a “national minority”—yet he never set foot in what was then China, and his offspring conquered the place. In north-east China lie the archaeological remains of the Koguryo kingdom of 37BC-668AD, the fount of Korean culture and myth. Chinese historians claim them as Chinese. Scholars and others thus project current political imperatives on to the past, and the notion of “minorities” affirms one big, longstanding Chinese family.

In Tibet the narrative is enforced with a few blandishments and many shows of state power. Like the Qing dynasty, the communists invaded Tibet on a pretext. Like them, they control the Buddhist religion by claiming a right to select lamas.

Qing precedent, over two centuries old, matters. Emperor Qianlong sent a golden urn to Lhasa, in which the names of candidates proposed for reincarnation would be placed. Its later use was fitful. But in the mid-1990s the urn was brought into service again. With it the communists chose their own Panchen Lama, the Yellow Hat sect's second-most-revered reincarnation. The Dalai Lama's earlier choice simply vanished. The boy, his family and the abbot who oversaw his selection have not been seen since. This month China's atheist leaders, led by President Hu Jintao, used the occasion of the Dalai Lama's 75th birthday to say bluntly that only they, with the golden urn, would approve the ageing man's reincarnation.

Low-altitude sickness

Now the government appears to be gearing up for a big celebration on October 27th of the 60th anniversary of the defeat of the “rebel” Tibetan army. Yet for all China's propaganda—and the new science suggesting how genetically close the two peoples may be—unity is elusive and “splittism” a constant threat. And now come signs of splits in Chinese circles over Tibet. Though many Chinese rally to the official line, even harder after anti-Chinese riots in 2008, others differ. Before their foundation was closed, some Beijing scholars last year wrote: “When you can no longer find work in your own land…and realise that your core-value systems are under attack, then the Tibetan people's panic and sense of crisis is not difficult to understand.” Some may dare to hope that such views will, one day, be allowed to be aired in polite company in China.

Meanwhile, Han Chinese flood in their tens of thousands each year on to the Tibetan plateau, making up in numbers what they lack in genetic disposition. As for Hu Jintao, he was first marked for great things when, as a younger cadre, he was the Communist Party secretary in Tibet. Little remains in folk memory of that time—except that Mr Hu suffered from high-altitude sickness and ruled Tibet from Beijing.





Economist.com/blogs/banyan