A mutation called delta-32 in the cellular receptor dubbed CCR5 protects against HIV infection, and is found more often in Europeans than other populations.What do you want to bet this will be used as fodder for the "Whitey invented AIDS to kill the black man" crowd?
There is a flip side to that notion: ancestral exposure to disease had more to do with the rise of the African slave trade than did any innate sense of superiority to, or disdain for, black people. This ancestral exposure led to resistance to Malaria, the bane of American coastal plantations. Possessing workers that were immune to the disease was a great boon to indigo and rice planters. This genetic mutation is also responsible for Sickle Cell disease, though.
Of course, if it weren't for the increasing difficulty of acquiring indentured servants from Great Britain in the late 1600s, the much-more-costly African trade would never have been pursued to such degree in the first place.