Kkkhhhaaannn!!!

My post, 1 in 200 men direct descendants of Genghis Khan, is linked up somewhere almost every week. Why is it so popular? No idea. But one thing that has come to mind: we've come a long way in since the early 2000s in assembling databases of human scientific genealogies. Soon enough a substantial proportion of the males in the human race will have their Y chromosomes typed. What proportion of these individuals are going to be part of a "star-shaped phylogeny," implying a radiation from a single individual relatively recently in the past? My own suspicion is a great deal. The Khan lineage is simply a relatively recent one as these things go. How did R1a1 come to be so widespread?