@usluck

If you believe in the

Answers in Genesis

material incest was not as harmful in the old days as it is today because there was more time for genes to be corruoted the closer to modern history you get

So if those people existed in different time periods that would explain why

Also all modern humans ancestors are traced to Noah who they might say was in the middle east

Middle East might give a more diverse gene pool even with Sibling marriage

If you believe that