As you admit, you are not a historian and have done no research on this. I encourage you to do the work to educate yourself on this. Biologically, there is no such thing as race in the way that we currently understand race in social terms. There are genetic variations within people who share ancestry, but those groupings are not biologically distinct races.
Our understanding of the human genome is relatively new, occurring long after the grouping of people into races, and the scientific evidence shows that these groupings are not based in biology. (How could they be? The creation of race is from a time when leeches were the height of science.)
In terms of Sickle Cell Disease, you can do some relatively quick Googling to find reading material showing that the prevalence of this disease in Black Americans can be traced to a relatively small number of specific African communities, including the Yorubans, Mandenkas, and Bantu people. Black Americans with that ancestry are linked to specific genetic communities, but we don't talk about the Yorubans as a race, because people of that ancestry have been folded into the larger grouping of "Black". |