A High-Tech Family Tree

Suzanne Critchfield, a 68-year-old grandmother in Oakley, Idaho, totes around her laptop to show off her latest acquisition: a family tree based on her DNA. She found the names of hundreds of ancestors in Denmark and England and, to her surprise, one in Spain. "You can only go so far back in the paper documentation," says Critchfield, an amateur genealogist who previously had tracked her roots to 17th-century Boston. "This goes back so much further, and it's so much more reliable." She has E-mailed other users of GeneTree.com who are newfound genetic relatives to trade family histories.

Suzanne Critchfield of Oakley, Idaho, shows her daughter, Annette Hansen, and grandchildren Mark, Bruce, Jared, and Alysha their DNA-based family tree.

(Kevin Horan/Aurora for USN&WR)

Anne Wojcicki was at brunch with friends in Silicon Valley the other day when they decided it would be fun to see which of them had a genetic predisposition for being a night owl. "I just pulled out a laptop," Wojcicki says. The friends logged on to her company's new website, where they all had stored their genetic profiles, and looked to see who had a DNA variation associated with altered sleep patterns. "It's kind of a fun thing with things like circadian rhythm, to see who you're similar to," says Wojcicki, cofounder of 23andme, a start-up in Mountain View, Calif., that sells individual gene scans.

Critchfield and Wojcicki are advance scouts in a sudden explosion of efforts to make something useful out of the human genome: genetics as a social networking tool. It's essentially taking DNA-testing capabilities used by medical researchers and wedding them to a social networking website like MySpace. Whether such retail genetics will create meaningful new human connections or be a mere hobby remains to be seen. But uncertainty hasn't dampened the enthusiasm of genetic entrepreneurs: "I'm convinced that in the next five to 10 years every educated person in the western world is going to have a profile like this," says Kári Stefánsson, CEO of Decode Genetics (decodeme.com), an Icelandic company that, like 23andme, started selling gene scans to the public in November at about $1,000 a pop. The truly adventurous can sign up later this month for the Personal Genome Project, which is recruiting 100,000 volunteers to post their entire genomes along with their medical information on the Web, where it can be probed by medical researchers—or genetic voyeurs. "It's an experiment, technological and sociological," says George Church, a Harvard geneticist who launched the nonprofit project, which he hopes will test the scientific and ethical issues surrounding genetics.

The scans that enable this new form of social networking are far different from older genetic tests that pinpoint genes that cause diseases like cystic fibrosis. Instead, they look for small variations along a human being's 23 pairs of chromosomes that can be used to gauge a predisposition for health problems like heart disease or diabetes—or to trace ancestry. Until very recently, such a broad scan—23andme charts 600,000 single nucleotide polymorphisms, or SNPs, and decodeme nearly twice that—would have cost millions. Still, SNP scans cover about 0.02 percent of a person's DNA, compared with close to 100 percent of the 3 billion bits of DNA in a whole genome scan.

Such wholesale disclosure of personal information could end up being dangerous for participants, Church acknowledges. They could find it hard to get health insurance or suffer other discrimination if, for instance, their genes reveal susceptibility to illness. "Some of them know they're going to get hurt, like astronauts and mountain climbers. But if enough of them see a benefit to themselves, their families, and society, then it will keep growing," says Church.

Share alike. The GeneTree website that Critchfield is using, which debuted in October, links genetic genealogy to paper genealogical records. The company is an offshoot of the Utah-based Sorenson Molecular Genealogy Foundation, which has collected DNA samples from people around the world to build a database for genealogical research. Critchfield found about 300 names to add to her genealogy on the GeneTree site, and hopes to get more from people she has E-mailed.

The notion of sharing genes on the Web debuted last year, when both Craig Venter, a leader in efforts to sequence the human genome, and James Watson, who shared a Nobel Prize for figuring out the structure of DNA, posted their genomes online. That quickly turned into a lesson in how genes can prove to be an embarrassment. In October, Watson made remarks disparaging the intelligence of Africans. In December, Stefánsson analyzed Watson's public genome and showed that 16 percent of the scientist's DNA came from a recent African ancestor, the equivalent of having an African great-grandfather.

Those kinds of surprises are not uncommon on the rough frontier of retail genetics. Eight years ago, Henry Louis Gates Jr., a professor of African-American studies at Harvard University, was among the first African-Americans to have his DNA tested in an effort to fill in the historical record of the slave trade. That test said his mother's family had Egyptian roots. But when he sent his DNA to a second company in 2005, Gates was told his maternal lineage was not African at all but European. It turned out that because the first company's DNA database had samples almost solely from Africa, it didn't pick up on the big surprise. Since then, Gates has turned to traditional genealogical research to make sense of the conflicting genetic data. "Most likely," he says, "I'm descended from an indentured servant who slept with a slave in the 17th century." In his new PBS series African American Lives 2, which will air in early February, he'll recount his search for that woman.

Gates recently joined with Family Tree DNA of Houston to launch AfricanDNA.com, which will augment DNA analysis with legwork by historians and anthropologists. "I want African-Americans to identify with Africa," he says. "I just don't want them to misidentify with Africa." He is philosophical about the glitches in his own genetic search. "I want people to be amused by this, intrigued by this, rather than defined by the process. It's a process still in its infancy."

Genetic analyses can be wrong for many reasons. DNA samples are easily contaminated; technicians can be sloppy; the technology is new and constantly changing; and the machines can generate "phantom mutations" (mistakes). Decodeme's Stefánsson points out that the startling discovery of African DNA in Watson's genome could be wrong because the original scan, done by another company, contains errors. (Some parts show Watson having two X chromosomes, impossible for a man.) Stefánsson says: "Genome sequencing, although it has taken enormous steps forward, is not yet there."

Tests for ancestry compare a person's DNA with that of others, so the larger and more accurate a genetic genealogy database, the more precise its results. (The accuracy of genome-based disease risk tests also depends on database size, as well as the accuracy of research that links certain mutations to specific diseases.) The National Geographic Society's Genographic Project, which has been collecting DNA from volunteers since 2005, has about 225,000 samples of mitochondrial DNA, which traces maternal lineage. Africandna uses 58,000 samples of mitochondrial DNA; GeneTree uses 53,000 mitochondrial DNA test results from the Sorenson database; 23andme tests against 1,000 samples. Companies don't always detail the size of their databases in promotional literature, and many customers don't know to ask. Hank Greely, a law professor at Stanford University and an expert on ethics and bioscience, says the industry all too often has the trappings of science without the substance. "Scientists tell you the limitations; they tell you what you're getting and what you're not," he says. "These guys don't."

Even the most diligent researcher may not find answers in the genes given the current technology. The first company Edward Ball used to test his DNA told him he was 13 percent American Indian. That was a surprise; in researching his 1998 book, Slaves in the Family, Ball, who is white, found evidence that he's related to African-American descendants of his forebears' slaves. Yet tests by two other genetic genealogy companies discounted the American Indian link. After further testing of his DNA and that of relatives, living and dead, through multiple companies and university researchers, Ball still doesn't have a clear sense of his genetic roots. "Most of us look at DNA as a sacred substance that has the deepest truths about human life," says Ball, who recounts the quest in his new book, The Genetic Strand. "The reality is, there are many ambiguities."

Raising the ante. Much has been made of the privacy risks posed by social networking sites like Facebook and MySpace. The new gene-testing sites raise the ante by encouraging customers to upload family trees, or even family medical histories. That information makes the data more useful for medical research—and also more potentially damning. A bill to protect people from discrimination by insurers and employers based on genetic information is stalled in Congress, and private DNA databases don't fall under the medical-records privacy provisions of state and federal law. There's nothing to keep a company from, say, selling the database as an asset if it goes bankrupt.

Church argues that since it's impossible to guarantee privacy, it's better to let it all hang out. (He has posted his health problems, which include heart attack, narcolepsy, and dyslexia, on his website with the wry aside, "Insurance companies take note.") His Personal Genome Project will ask participants to take an entrance exam showing that they understand the privacy risks posed for themselves and relatives. When one person posts DNA online, for instance, it reveals 50 percent of the genetic variation in the person's parents and children. "I encourage the first family member to check it out with the rest of the family before they do anything public with their data," Church says.

Even good tidings from our genes must be taken with a grain of salt. Stefánsson's risk of Alzheimer's, as calculated by the decodeme site, is 49 percent lower than that of other men of European ancestry. That result comes from calculations on the risk posed by variations in a gene, APOE, that studies have associated with Alzheimer's. But the APOE variant is just one factor. Others are age, cardiovascular disease—and chance. Understanding of how those factors relate is imperfect at best. Yet uncertainty, he says, is no reason not to see genetic scans as a useful tool. "There are a lot of people out there who just want to learn more about themselves."