DNA test’s ability to pinpoint African roots is doubted

WASHINGTON – When DNA testing was offered as a way to trace black family heritage three years ago, it seemed, at long last, that African Ameri- cans whose histories were lost in the trans-Atlantic slave trade had found a way home.

TV talk-show host Oprah Winfrey took a test that linked her to the Kpelle people of what is now Liberia. Composer Quincy Jones was informed that he is a likely descendant of the Mbundu or Kimundu tribe in present-day Angola, and Harvard University professor Henry Louis Gates Jr. was told that his ancestry is Nubian.

Each test was conducted by African Ancestry Inc., a Washington firm that claims exclusive rights to the most comprehensive database of DNA sequences from Africans.

African Ancestry executives say this large database makes it possible to pinpoint one’s origin to a specific region and sometimes tribe.

“It can be done,” said Gina Paige, a co-owner of the company. “We don’t always just find one group. We tell the client what we find. We determine our results based on the frequency of matches.”

But ever since the tests began in 2003, questions have been raised about their accuracy: specifically whether tracing mitochondrial DNA, which is passed from the mother’s side of the family, can reliably pinpoint tribal origins.

Those doubts were given a public voice this week with the publication of an article in a British peer review journal. It said a study found that fewer than 10 percent of black Americans whose mitochondrial DNA was identified matched perfectly with a single African ethnic group, and 40 percent had no match.

The authors relied on a study that compared DNA sequences from 170 African Americans with DNA sequences from 3,700 Africans who live below the Sahara. “The finding … suggests that few African Americans might be able to trace their … lineages to a single ethnic group,” the article said.

At best, said the article’s co-author, Bert Ely, a professor of biological sciences at the University of South Carolina, the test can give people only a probability that they hail from a specific region on the African continent rather than a specific ethnic group.