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Dartmouth College Office of Public Affairs • Press Release
Study of the genetic code of more than 3,000 Africans and African-Americans finds surprisingly few ancestral groups
A Dartmouth Medical School researcher is part of the team that has determined that Africans are descended from 14 ancestral populations. The study is published in the April 30 edition of Science Express, the advance online publication of the journal Science.
“I can’t stress enough the historical importance of this work,” says Jason Moore, professor of genetics and of community and family medicine at Dartmouth Medical School, and an author on the paper. “It will be cited for many years to come and provides one of the best examples of how genetics can be used to understand the origins of all humans.”
The lead author on the paper is Sarah Tishkoff with the Departments of Genetics and Biology at the University of Pennsylvania, and she led the research team of 25 collaborators in analyzing samples from 121 African populations, 4 African-American populations, and 60 non-African populations, representing more than 3,000 individuals. The study, in part, used data that had been gathered over the last 10 years by Moore and co-author Scott Williams, with the Center for Human Genetics Research at Vanderbilt University, for one of the largest population-based genetic studies in Africa (the Hypertension and Arterial Thrombosis (HeART) study) to identify genetic risk factors for common human diseases.
“Our samples, along with others from around Africa and elsewhere, were used by Dr. Tishkoff and the co-authors to provide this first comprehensive analysis of the genetic structure and history of Africans and African Americans,” says Moore.
The study reveals that Africans originated from fourteen ancestral population clusters that correlate with ethnicity and shared cultural and/or linguistic elements.
The paper states, “We observe high levels of mixed ancestry in most populations, reflecting historic 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.”
In addition to Moore, Tishkoff, and Williams, the international team on this paper includes individuals from the Max Planck Institute of Evolutionary Biology in Germany; the University of California, Los Angeles; the Università di Ferrara, Italy; Musée de l’Homme, Paris; Ohio State University; Ministère de la Recherche Scientifique et de l’Innovation, Cameroon; University of Bamako, Mali; University of Khartoum, Sudan; University of Stellenbosch, South Africa; Muhimbili University of Health and Allied Sciences, Tanzania; U.S. Environmental Protection Agency; Center for Biotechnology Research and Development, Kenya; University of Maryland; National Cancer Institute; International Biomedical Research in Africa, Nigeria; and the Marshfield Clinic Research Foundation, Wisconsin.
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