Ancestry.com simply does not do what you're claiming here. The whole "fun" of ancestry.com is that each person who does it shows up in surprising places across

Ancestry.com simply does not do what you're claiming here. The whole "fun" of ancestry.com is that each person who does it shows up in surprising places across the globe, regardless of their supposed "race", because genetics don't adhere to any concept of "race" as it exists in culture. And the this Barrier Theory was proposed by eugenicists in the 20s and thoroughly debunked by the 30s.