Thursday, October 19, 2006


Another good use for DNA testing

Most of us know where we came from, at least as far back as we care to find out — my paternal grandparents and maternal great-grandparents are from various parts of eastern Europe. But what's it like not to know? Suppose I could only say that my ancestors came here in the early 1800s from somewhere in Europe, but I had no idea where?

More specifically, suppose I could only say that my ancestors were dragged here in chains on slave ships in the early 1800s, from somewhere in Africa? I think I'd like to know more. The Washington Post reports on the mixed success of using DNA testing to trace African roots.

As the article reports, it's not always accurate. Still, it seems a useful way to narrow things down, to give one an idea where there'd been no idea before. But the questions of accuracy are heightened now, with a recent study:

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.

The article goes on to say that the testing may be able to point people at a region, but not a specific tribe or ethnic group. That alone, though, ought to be useful: with a continent as large as Africa, I think it would be good to know that you came from, say, Congo, rather than Senegal or Angola. It can give one a starting point for learning more.

The company's client list includes a batch of celebrities who've apparently been happy to know something. It would be interesting if we could hear what Alex Haley thought of this.

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