What seems to be true (from preliminary studies) is that the gene variants that were under strong selection (reached fixation) over the last 10k years are different in different clusters. That is, the way that modern people in each cluster differ, due to natural selection, from their own ancestors 10k years ago is not the same in each cluster — we have been, at least at the genetic level, experiencing divergent evolution.

In fact, recent research suggests that 7% or more of all our genes are mutant versions that replaced earlier variants through natural selection over the last tens of thousands of years. There was little gene flow between continental clusters (“races”) during that period, so there is circumstantial evidence for group differences beyond the already established ones (superficial appearance, disease resistance).

http://infoproc.blogspot.com/2008/01/no-scientific-basis-for-race.html