Article

The Genetic Structure and History of Africans and African Americans

Department of Biology, University of Maryland, College Park, MD 20742, USA.
Science (Impact Factor: 31.48). 06/2009; 324(5930):1035-44. DOI: 10.1126/science.1172257
Source: PubMed

ABSTRACT Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations
across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African
populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral
population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties.
We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent.
Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers
and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other
African (~8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the
complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies.

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