> paper once about two ancient South American
> villages only about 2km apart and all the graves
> in each village were a single mtDNA type and
> different from the other village. I need to do
> some more reading this. Its hard to buy. This
> would require some sort of pervasive cultural
On second thought, maybe this could result from extremely rigid matrilineal tribes since the mtDNA lineage would be passed down from one matriarch. There are actually legends of ancient matrilineal cultures in South America.
It seems like it would be possible that 20k years of marriage only within the same matrilineal tribe could result in some serious gene drift and result in very different skull shapes.