A new study suggests Africa is the source of all modern humans as the genetic structure of Africans is traced to 14 ancestral population clusters that correlated with ethnicity and shared cultural and/or linguistic properties.
The largest-ever study of African genetic data—more than four million genotypes--also found startling diversity on the continent, shared ancestry among geographically diverse groups and traced the origins of Africans and African Americans.
Researchers studied 121 African populations, four African American populations and 60 non-African populations for patterns of variation at 1327 DNA markers. The study traced the genetic structure of Africans to 14 ancestral population clusters, which correlated with self-described ethnicity and shared cultural properties.
The research team demonstrated that there is more genetic diversity in Africa than anywhere else on earth.
The study was published in the April 30 issue of the journal Science Express.
"Given the fact that modern humans arose in Africa, they have had time to accumulate dramatic changes" in their genes, explained lead researcher Sarah Tishkoff, a geneticist at the University of Pennsylvania.
People have been adapting to very diverse environmental niches in Africa, she said.
The study also provided 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.