Genome Study Points to Adaptation in Early African-Americans

NY Times ^ | January 2, 2012 | NICHOLAS WADE

[Wonder Warthog]

"Oh yeah, because conditions on the veldt were so idyllic."

Conditions don't have to be "idyllic".....just different.

[RegulatorCountry]

Forced selection for the sickle cell trait is not natural. The premise is false, as is the conclusion.

[Wonder Warthog]

"Forced selection for the sickle cell trait is not natural. The premise is false, as is the conclusion."

ANY "selection pressure" is "forced" in some fashion or other. That "force" may be a mountain range, continental drift, a shifting river course, or human intervention. You seem to be hung up on the fact that these groups were made slaves and lost their freedom...which is totally irrelevant to the question of evolutionary change. The "selection pressure" on Ashkenazi Jews was also "human imposed", and thus, by your lights "not natural". Mother Nature doesn't care one way or another.

[El Gato]

The false premise here is that early African-Americans as a group were free to “select” and reproduce

I'm skeptical too, but the "selection" would occur as people died before being able to reproduce, whether they chose who they reproduced with or not. Of course lots of European genes were introduced by slaveholders and their overseers.

[RegulatorCountry]

Of course lots of European genes were introduced by slaveholders and their overseers.

Overseers, yes. Widespread antipathy still toward Scotch-Irish, who comprised the majority of overseers. Owners? Not so much as pop culture and politically motivated historical revisionism would lead one to believe. It happened but was not all that common.

Scan back upthread for the link provided by AdmSmith, which provides the most common means of introduction.