"A mutation in the gene that is thought to affect red blood cell production was present in only 9% of the Han population, but was found in 87% of the Tibetan population."

Okay, so according to the news article kindly submitted here, the gene pattern is not invariant in the Tibetan population, nor is it absent from the non-Tibetan population. And this is what we would expect from hundreds of previous studies of human genetics--there is genetic variation within each geographically defined human population, even when the populations are under very strong selection pressure (as here, for this trait). And note too the "thought to affect red blood cell production," as gene mechanisms are still generally very poorly understood.

Way back in the 1970s, I had a student part-time job in the medical school of the University of Minnesota, and one of the physician-professors there then was writing grant applications to try to get to Tibet to study high-altitude adaptations that were presumed to be present in populations that had lived on the high Tibetan Plateau since thousands of years ago. It has taken a long time even to confirm that hypothesis, but already we see that some Tibetans live at high altitude, as their ancestors have for a long time, WITHOUT those gene adaptations. Individual human adaptability is amazing, in many ways even more amazing than the selection pressure on gene assemblages that gives me my white skin (the ancestral human condition was surely dark skin). Human beings can climb Mount Everest without bottled oxygen (please don't try this at home) and humans from whatever ancestral region can live in whatever other region of the world, perhaps in discomfort, but can grow and reproduce there. Human adaptability is quite amazing.

AFTER EDIT: To answer a question I was asked,

Are you pushing in the direction of "Tibetans are indistinguishable from Chinese and Tibet is China"?

No, my answer was not political. (I don't have a Free Tibet bumper sticker on my car, as many of the drivers in this state do, but I'm generally sympathetic with that point of view as to the national sovereignty of historical Tibet, which includes a lot more territory than the current Tibet Autonomous Territory administered by the P.R.C. regime in China.) My statement is biological and VERY general--every genetic study of every geographically defined population in every part of the world finds gene variation in that population, and many of the gene variants found are known to occur in other populations. (Checks for freely downloadable links to post here.)

http://www2.webmatic.it/workO/s/113/pr-1400-file_it-Barbujan...

http://www2.webmatic.it/workO/s/113/pr-1611-file_it-Barbujan...

So, no, even if two populations are all but indistinguishable on genetic grounds (Norway and Sweden come to mind), there may be grounds for distinct national governments, on historical and geographic and cultural grounds, and even if a national population includes substantial genetic diversity within the basic human pattern of all of us being very similar (for example, the United States, or Canada, or Russia, or China), there may be grounds for preserving national unity that groups together substantial genetic diversity. (Again, I must stress that human beings have exceptionally little species-wide genetic diversity, but what diversity they have is found within even narrowly defined geographic populations.) The political issue has nothing to do with the scientific issue of looking for genes.