The next step is to find out what biological difference imparted by this genetic difference causes selection to favor that variation over the others.

If we look at multiple genes, the ethnic variations such as the ones we found are likely to be counterbalanced by other differences. Just because these genes are still evolving, doesn't necessarily mean they make you any smarter. We've evolved genes for selfishness, violence, cruelty û- all of which are in place because they may make survival easier.

In a very short period of time, this class of variants arose from a single copy to many copies. That implies that this must have happened because of positive selection.

My concern is that this is going to become justification for prejudices against certain groups.

If we look at multiple genes, the ethnic variations such as the ones we found are likely to be counterbalanced by other differences. Just because these genes are still evolving, doesn't necessarily mean they make you any smarter. We've evolved genes for selfishness, violence, cruelty û- all of which are in place because they may make survival easier.

Meanwhile, our environment and the skills we need to survive in it are changing faster then we ever imagined. I would expect the human brain, which has done well by us so far, will continue to adapt to those changes.