For this study, the mitochondrial DNA (mtDNA) control region (16024-576) was Sanger-sequenced for a total of 2,563 self-identified African Americans, using automated processing techniques and data review standards exceeding guidelines for forensic applications.
Genetic diversity ranged from 0.9952 to 0.9998 in 22 population samples from 20 different States. Haplogroups of African ancestry, found in 82.48 percent of individuals overall, were most concentrated in the Southeast U.S. and decreased to the north and west. West African and West Central African haplotypes were well-represented in the population samples, especially in the southern U.S. States, while East African haplogroups were observed in low-frequency clusters in a handful of locations across the country. East Asian, Native American, and West Eurasian admixture was present in 3.16 percent, 2.93 percent, and 11.43 percent of samples, respectively. Although some geographic substructure was detected across the population samples as clines in admixture frequencies, 20 of the 22 population samples were found to be statistically indistinguishable by pairwise comparisons and AMOVA calculations. Datasets from Hawaii and Idaho, however, were clear outliers. Overall, these more than 2,500 control region sequences represent the most comprehensive regional sampling of African American mtDNA diversity to date, and are suitable for use in a forensic mtDNA database. The population data are made available via EMPOP (www.empop.org) and GenBank. (Publisher abstract modified)