When the paper trail that Raymond A. Winbush followed in search of his African roots ended at a slaveholding Kentucky plantation, he turned to a combination of modern technologies: genetic testing and online social networking.
It worked. A DNA test traced his ancestry to tribes in Cameroon and Equatorial Guinea, and an online forum set up by the company that scanned his DNA put him in touch with other African Americans who share similar genetic markers.
"It's like an electronic family reunion," said Winbush, director of the Institute for Urban Affairs at Baltimore's Morgan State University.
The online networking that he used marks a new and potentially lucrative frontier for genetic testing companies, which have witnessed the success of sites such as Facebook and MySpace.
Although they don't have much in common at first blush, genetic tests and online social networks aim to connect people. Social networks use the World Wide Web to link the living, whereas genetic tests -- employed here more out of curiosity than medical necessity -- use DNA to tie the living to long-dead ancestors.
The forum that put Winbush in touch with others who shared his heritage was a relatively simple networking program offered by African Ancestry, the company that scanned his DNA.
Other DNA-testing companies, such as California-based 23andMe and Vancouver, Canada-based Genetrack Biolabs, offer more elaborate networking sites.
"All of these companies are thinking of a social networking component -- or what that would look like," said Duana Fullwiley, a medical anthropologist at Harvard University.
Some sites, including African Ancestry and 23andMe, limit their social networking functions to customers who have paid for genetic tests.
Genetrack Biolabs takes a different approach. It opens its network, Genebase.com, to the public and markets genetic tests to those who join. The site has grown from 200,000 members in August 2006 to more than 675,000 users last month, company officials said.
About two dozen companies offer commercial DNA testing, which costs between $100 and $1,000, depending on how many genetic markers are analyzed. Numbers are hard to come by, but an article in the journal Nature estimated that more than 460,000 people purchased tests from 2000 to 2006. Experts agree that the business has grown even more rapidly since then.
The trend isn't lost on investors. Ancestry.com, a genealogy website that claims more than 15 million users and offers a mix of social networking and genetic testing, was recently sold to a private equity firm for $300 million.
Critics say that these genetic tests are based on questionable scientific assumptions and reveal only a tiny corner of a human's ancestral tapestry.
"At most, you're getting 1% of your ancestry, genomically speaking," said Fullwiley. "What it tells you is a little part of your genome is present in people who live in an area in the present day."
She sees technical problems with the tests. For one thing, they assume that because a genetic marker is common among people living in a particular region today, that population has remained relatively static over time.
Backers of genetic testing counter that knowing a little is better than knowing nothing. They say tests can offer important clues to help reconstruct family trees.
For Winbush, the genetic test and online network bridged a gap between Kentucky and Africa. Using his mother's birth certificate, he had traced his family back to a slave-era plantation in Kentucky where his great-great-grandfather was listed in county documents as a "4-year-old mulatto boy."
"The word 'mulatto,' " Winbush said, "was a code word the slave owners used to say that 'these were my children.' "
But the records could take Winbush no further, so he decided to see what a genetic test could tell him.
His paternal DNA linked him to the Bubi, a people indigenous to Equatorial Guinea on Central Africa's Atlantic coast, and his maternal DNA linked him to the Tikar people of adjoining Cameroon. He also carried markers common in people of Dutch, French, British and German origin.
"The discovery helped me to locate myself more psychologically," he said. "It's all kind of wrapped up in the idea of locating oneself in history."