Study Shows Difficulty of Tracing African Roots

African Americans hoping to use DNA to find their roots may have to look harder than previously thought, researchers said Thursday in a study suggesting Africans are too genetically mixed to make tracing easy.

Several companies now offer to help Americans trace their African ancestry using mitochondrial DNA, which is passed from mother to children virtually unaltered.

But biologist Bert Ely of the University of South Carolina and colleagues, who published their report in the online journal BioMed Central Biology, found that fewer than 10% of African American mitochondrial DNA sequences that were analyzed can be matched to any single African ethnic group.