Humans are very unusual from a genetic perspective that makes analysis of us difficult. Firstly, the population has expand hugely in a very short time so there

Humans are very unusual from a genetic perspective that makes analysis of us difficult. Firstly, the population has expand hugely in a very short time so there are all sorts of founder effects. Secondly, the selection presure completely changed a few thousand years ago with the transition from hunter-gather to farming. These two factors make it really hard to use the normal genetic tools and concepts to study human evolution and draw accurate conclusions.