When the paper trail that Raymond A. Winbush followed in search of his African roots ended at a slave-holding 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, while 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 a electronic family reunion," said Winbush, director of the Institute for Urban Affairs at 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 both aim to connect people. Social networks use the World Wide Web to link the living, while 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 Silver Spring company that scanned his DNA.
Other DNA-testing companies, such as California-based 23andMe and Vancouver-based Genetrack Biolabs, offer more elaborate networking sites with multiple communication channels, including the sort of personal profiles, "friending" features and specialty groups pioneered by general-interest sites like Facebook and MySpace.
"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.
Genetrack allows users to build a family tree and connect with other members through common ancestors or surnames. Members who take the genetic test can opt to share their results and thus find people with similar genetic profiles.
"It's social networking with a real purpose," said the company's president and chief executive officer, Dr. June Wong. "With Facebook, people are just connected as friends. With Genebase, people are connected through biological linkages."
About two dozen companies now offer this kind of commercial DNA testing. 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 Web site that boasts 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.
To take the test, a customer scrapes the inside of his mouth with a swab and mails it to the laboratory. The lab extracts genetic material from cells on the swab and compiles a digitized DNA map. The customer's DNA markers are then matched with markers common in people from certain parts of the world.
There are two common analyses. One traces a man's paternal lineage by analyzing markers on the Y chromosome that he inherited from his father. The other looks at mitochondrial DNA, which humans inherit from their mothers, to trace maternal ancestry.
Some who use these services hope to find out if they're related to famous people, such as singers Bono or Jimmy Buffett, or to historical figures such as Marie Antoinette or Jesse James. Others, like Winbush, want to fill in gaps in the family tree or find out what part of the world their ancestors hailed from.
However, 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 percent of your ancestry, genomically speaking," said Harvard's 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 glaring technical problems with the tests. First, 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.
Africa is one example of a place where those assumptions might not hold up, Fullwiley said. "Just because we fix these tribes and those tribes in a place doesn't mean they have always been there or haven't changed. Africans were dropped off all over the West Coast of Sierra Leone after slavery was made illegal. There was a lot of mixing that went on."
Even if assumptions about the origins of genetic markers do hold, she said, testing companies use only a small number of markers (paternal and maternal tests each look at 1 percent of possible markers) to tie customers to certain regions and ethnic groups. Because the results offer only a small glimpse of a person's total genetic heritage, consumers should be wary about basing their identity on them, Fullwiley said.
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.
Genetrack's Wong mentioned one of the company's customers, a 59-year-old man who had been adopted as a child and tracked down his biological family through Genebase.
"He found a man on the network who shared 44 out of 44 genetic markers on his Y chromosome," she said. "He found out there was a baby in the man's family who was put up for adoption 59 years earlier. Turned out he was the man's cousin."
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 near Princeton County, Ky., 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 in Central Africa, and his maternal DNA linked him to the Tikar people of 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."
In an online forum, he found he shared more than genetic markers with other people of Tikar descent. "They were all very tall people," said the 6-foot-5-inch Winbush.
Now he and his newly discovered - if distant - relatives want to translate their new sense of place into action.
"I've been able to connect with people from all over the country who have taken the test," he said. "We are talking about raising money and going over there and seeing what people need."