That is, in the African American sample in the HapMap3 population set. I was just browsing the Admixture manual, and stumbled onto this plot:

CEU = Utah Whites, and YRI = Yoruba. They should be familiar from the previous versions of the HapMap. MEX = Mexican Americans from Los Angeles. K = 3, three ancestral populations. So what’s ASW? “African ancestry in Southwest USA.” I was struck by the high proportion of what seems to be Native American ancestry in some of the African Americans. This is a controversial aspect of scientific genealogy, as most researchers have found far less Native American ancestry within the African American population that had been the expectation within the community (Henry Louise Gates Jr. had to face criticism and skepticism when reporting this result from the black public). These results would conflict with that. But here’s the fine print on this sample. All you really need to know is this: “Principal Investigator for Community Engagement and Sample Collection: Morris Foster, University of Oklahoma, Norman, Oklahoma.” Oklahoma used to be called “Indian country,” and most Americans are aware that whites and blacks in this part of the country have more than the usual fraction of indigenous ancestry. Just something to keep in mind when encountering results that come out of HapMap3 populations.