This always gives me pause when I read it. Ten thousand years is a very long time. Selective breeding creates varieties with very strong tendencies. Dog breeds are an example on a short time scale. Purposeful yes, but ten thousand years of having to defend against the now warlike culture we live in may well have had a affect on human genetics. The very fact that different groups have different tendencies even when they move away from their place of origin is compelling.
I look forward to your research on the subject but in all honesty it will take some doing to remove my thought that ten thousand years is a very long time even it it is relatively short in the total history of mankind. It is also the most recent.