When DNA testing was offered as a way to trace black family heritage three years ago, it seemed, at long last, that African Americans 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.
Some researchers, while having qualms with African Ancestry’s claims, say DNA testing is useful when combined with other genealogical tracing tools, such as historical records, folklore and archaeology. “It’s probably true that most of the time you’re not going to find an exact match,” said Jason Eshelman, a molecular anthropologist, who founded Trace Genetics, another DNA testing company, “but there is other information you can tease out to suggest origin.”
But some scientists such as Ely, though sympathetic to the quest of African Americans to discover their antecedents, say probability of hailing from a region should not be confused with certainty of descending from a specific tribe. Officials at African Ancestry counter that when it comes to a history-starved race, probability is a good enough place to start.
“It was hard until now to know where I came from in Africa, and the information that my ancestry test has given me is a tool kit that I can use with courthouse records,” said Michael Darden, a company spokesman. “Knowing that is better than nothing.”
Most black Americans descend from West Africa, where the vast majority of slaves were seized. After surviving the brutal trans-Atlantic voyage to the Americas, they were forbidden from speaking the tribal languages from regions that are now known as Angola, Senegal, Ghana, Liberia, the Ivory Coast and Nigeria.
Mitochondrial DNA can point the way home. While it makes up a tiny fraction of all DNA found in a cell, its link to maternal roots is crucial for black Americans. The maternal side of a black family almost always goes back to Africa, as opposed to the Y chromosome of the father.
Thirty percent of Y-chromosome tests in black Americans lead to Europe, the origin of white men who fathered mixed-race slaves—often from rape.
African Ancestry is owned by Rick Kittles, who obtained exclusive rights to the world’s most extensive database of individual African DNA sequences. Kittles has refused to share his database, angering other researchers who have a much smaller pool of information from which to draw.
On its Web site, African Ancestry asserts that three years ago it was the first to offer testing. Its client list includes actors Whoopi Goldberg, Isaiah Washington, LeVar Burton and Chris Tucker; film director Spike Lee; and former U.N. ambassador Andrew Young.
Gates, who worked with Ely and Kittles for his PBS documentary, “African American Lives,” said they are honest men who disagree. But, he added, DNA testing without a historical analysis is useless.