Very recent altitude adaptation in Tibet

Nick Wade in The New York Times is reporting on a new paper which will come out in Science tomorrow which investigates the evolution of genes implicated in adaption to higher altitudes among Tibets. I've posted on the genetics of this topic before, it obviously is of great interest. The major new finding is that these adaptations seem to have spread among Tibetans very recently, on the order of 3,000 years or so. Here's the relevant section on the genetic architecture: