Where We Come From
Recent advances in genetics are starting to illuminate the wanderings of early humans
No lifeguards. But geneticists fear that for every Pearl Duncan who boldly dives into the gene pool, at home with her mixed racial history, other more naive searchers may be dismayed at what they find. "Five percent of the people in America are sending Father's Day cards to the wrong guy," says Martin Tracey, a professor of genetics at Florida International University in Miami. What's more, mitochondrial and Y DNA reveal just a tiny slice of family history. Only one out of four great-grandfathers is represented on the Y, for instance, and only one great-grandmother in mitochondrial DNA. Go back just five generations, and only one of 16 forefathers is revealed. Thus someone seeking African roots could have DNA tests come back purely European, even though the person has largely African ancestors. "It's really dangerous to market a single locus as a statement of identity," says Emory's Wallace, who counsels patients with devastating genetic diseases. "I don't want to say to someone, `I believe you're a Native American, but your mitochondria are European.' "
Indeed, few genetic genealogists will experience the same thrill as Adrian Targett, a schoolteacher in Cheddar, England, who discovered through DNA testing that he's a blood relative of Cheddar Man, a 9,000-year-old skeleton found in a nearby cave. But some people, those who seek answers to very specific questions, say they get their money's worth (box, Page 40). Doug Mumma, a 65-year-old retired nuclear physicist in Livermore, Calif., searched out strangers with his surname all over the world and paid $170 per sample to have their Y chromosomes tested. Many turned out to have no genetic link to Mumma, but he did locate several blood relatives in Germany. Mumma says, "To me it's cheap for what I want to do."
[Picture captions]
Philadelphian Bill Swersky (left) had DNA testing to confirm his heritage as a member of the cohanim, the Jewish priestly caste; he discovered that Andy Carvin of Washington, D.C., is a distant relative.
Manhattan writer Pearl Duncan gathered DNA from Ghanaian churchgoers in New York and had it compared with her father's genes in her quest to reconstruct her family's genealogy.
California retiree Doug Mumma used the Internet to find people around the world with his surname, then paid for Y chromosome testing that identified a few blood relatives in Germany.
Retired Navy Petty Officer Greg Spragins, 41, of San Diego, wasn't surprised when DNA testing suggested he has some Jewish roots: He's part Indian, too. "My family is mixed anyway."
Alaskan Aleut elder Alice Petrovilli is helping conduct DNA research into the origins of her people, who probably crossed the Bering Land Bridge from Asia about 9,000 years ago.
Genealogy by the genes
For-profit genetic genealogy services are springing up, but they can answer only limited questions.
Family Tree DNA (713-828-4200, www.familytreedna.com) helps connect distantly related "genetic cousins."
GeneTree (888-404-4363, www.genetree.com) tests whether families with the same surname are related.
Oxford Ancestors (www.oxford ancestors.com) groups people into ancient maternal and paternal lineages.
Ancient history in the DNA
advertisement
