Tibetans, Chinese, and Evolution

http://www.nytimes.com/2010/07/02/science/02tibet.html?_r=1

Now this is very interesting.  I think I'll send this to my old East Asian history professor to see what he's got to say about it.  I'm mostly interested in the "population bottleneck" among the Han Chinese and what events in Chinese history might explain that.

Although I've always been interested in science, I haven't been keeping up to a large degree with the use of genetics to track ancestry.  The most recent news item I recall based on that subject involved the exact timing of the divergence between humans and other primates and since it was posted on my alternate-history forum, the headline (which had to do with when humans and apes stopped mating with each other) provoked a lot of crude humor.