A somewhat dated article, from the November-December issue of American Scientist may be of interest, even if a bit off the "mood" of the thread thus far.

"Black" and "White" Not Quite Right appeared in a marginalia column. Some things at this magazine's site require special access, but I believe this one should be "publicly available."

The article must be read pretty carefully, since it really applies only to the Brazilian population studied. The "killer statement" - out of context a bit here - was:

"..., there were no significant differences in the African genomic ancestry of black and white study participants."

While I didn't find the result surprising, especially in context, knowing as much as possible about the reality may be useful when faced with those adherent to unreal beliefs.

For reference, publication of the full study report is cited as appearing in the January 2003 issue of the Proceedings of the National Academy of Sciences of the United States of America.

John