They swab the cheeks of strangers and pluck hairs from corpses. They travel hundreds of miles to entice their suspects with an old photograph, or sometimes a free drink. Cooperation is preferred, but not necessarily required to achieve their ends.
If the amateur genealogists of the DNA era bear a certain resemblance to members of a "CSI" team, they make no apologies. Prompted by the advent of inexpensive genetic testing, they are tracing their family trees with a vengeance heretofore unknown.
"People who realize the potential of DNA," said Katherine Borges, a co-founder of the International Society of Genetic Genealogy, "will go to great lengths to get it."
Unlike paper records, which can be hard to come by and harder to verify, a genetic test can quickly and definitively tell if someone is a relative. But not all potential kin are easily parted from their DNA. Some worry about revealing family secrets. Some fear their sample could be used to pry into other areas of their lives. Some just do not want to be bothered.
Those cases inspire tactics that are turning the once-staid pursuit of genealogy, perhaps second only to gardening among American hobbies, into an extreme sport.
Derrell Teat, 63, a wastewater coordinator, recently found herself staking out a McDonald’s. The man she believed was the last male descendant of her great-great-great grandfather’s brother had refused to give her his DNA. So she decided to get it another way.
"I was going to take his coffee cup out of the garbage can," said Ms. Teat, who traveled to the Georgia mountains from Tampa, Fla., with her test kit. "I was willing to do whatever it took."
Darrell Teat determined in her research, once waited outside a restaurant with a test kit hoping to capture a reluctant would-be relative's DNA on a coffee cup. (photo by Melissa Lyttle for The New York Times)
At one time, she might have been satisfied with a cousin’s census research, which revealed that they had descended from one John B. Hodgins living in South Carolina in 1820. But a DNA test of an Oklahoma Hodgins, who was found through the phone book, confirmed they were related. Now Ms. Teat wants to identify all of John B.’s living descendants by July, when she will preside over a Hodgins family reunion.
Alas, cornered in his garage, Ms. Teat’s quarry refused to listen to her pitch. Perhaps he thought she was seeking a paternity test. In any case, he did not show at his usual breakfast spot.
"It drives me nuts," Ms. Teat said. "Knowing I can get to the bottom of it, if people would just cooperate."
By next year, close to half a million people will have taken a DNA genealogy test, according to estimates from companies that provide them. The tests detect genetic markers that distinguish the descendants of an individual and reveal if two people share a recent common ancestor.
Seeking to expand their family trees, thousands of amateur family historians have begun asking people with the same last names to compare genes, even though most are total strangers. That is where the free drinks come in.
"I always say, never ask for DNA on a first date," said Georgia Bopp, 65, a retired banker in Kailua, Hawaii. "A courtship is involved."
Ms. Bopp woos with family tree diagrams from Web sites like Ancestry.com. Only after several e-mail exchanges does she mention DNA, and then she is quick to clarify that the test does not involve needles.
But when a detour on a recent trip brought her within miles of the only living male descendant of her maternal great-grandfather, she went for the direct approach. Determined to get the purest sample, she grabbed his glass at a local restaurant before the waitress filled it.
"Have you had anything to eat or drink in the last hour?" Ms. Bopp asked, whipping out the DNA kit stashed in her purse.
"She wanted my saliva, basically," said Warren Lenhart, 60, a foreign policy analyst whose test confirmed that they both had descended from a man who emigrated to Philadelphia from Germany in 1748. "There was no time for small talk."
DNA genealogy tests hold out new hope for adoptees like Paul Gilbert, 77, of Los Angeles. Searching for his biological relatives, Mr. Gilbert uncovered his birth mother’s name in records, which pointed him to a man he believed to be his half-brother. But the man was not eager to verify it through a DNA test. "I can’t imagine my father consorting with a woman like that," he wrote to Mr. Gilbert of his mother.
When the man finally came around, Mr. Gilbert, a retired lawyer, was just as glad that there was no genetic match. "He didn’t sound very nice," he said.
Since learning that she shares some markers with St. Luke the Evangelist, Kathy Johnston, 54, a dermatologist in Torrance, Calif., has been lobbying to have the saint’s remains more thoroughly analyzed.
She believes St. Luke’s mother was Celtic, as is her own lineage, not Syrian, as previous genetic tests on remains in Padua, Italy, have suggested. She is willing to pay for the test, but scientists at the University of Ferrara and the Roman Catholic Church have ignored her theories.
The basic tests are sold for $99, a small fraction of what they might have cost a decade ago. But test 40 relatives, and costs can add up.
To her husband’s dismay, Melissa Robards, nee Springer, has spent more than $1,000 testing Springers around the country to see if they are related. She has been known to send flowers to stubborn holdouts.
More drastic measures may be necessary to secure DNA from the talk-show host Jerry Springer, who has so far ignored her three e-mail messages. Ms. Robards, a 55-year-old mother of two in Sparks, Nev., has not entirely dismissed posing as a cross-dresser to get on his show.
There is, after all, only so much time. DNA may be the essence of life, but it is the fear of impending death that drives the current genetic genealogy frenzy. "If you don’t catch the people before they die," Ms. Robards said, "you’re out of luck."
Not necessarily. Susan Meates, a retired business executive, has discovered dozens of cousins because of her campaign to salvage her brother’s DNA in the hours after his death in a car crash.
Ms. Meates prevailed on her brother’s former wife to retrieve his clothes from the funeral home and put them in her refrigerator. From North Carolina, she instructed the medical examiner in Maryland to save blood from the autopsy and persuaded the mortician to take a cheek swab.
Some funeral homes now offer post-mortem DNA collection. But Linda Jonas saw no need for professional help when she tugged several hairs from her grandmother’s head as she lay in her casket.
She made sure to get the root.
"Obviously, it’s not going to hurt her," said Ms. Jonas, a family historian in McLean, Va. "I had a little Ziploc."
Genetic testing companies encourage the use of cheek cells whenever possible, but that does not stop customers from dispatching DNA in a multitude of forms. For a premium, Family Tree DNA, a provider of the tests, has extracted genetic material from toothbrushes, hearing aids, nail clippings and postage stamps. (Hair remains tricky).
The talismans come mostly from people trying to glean genealogical information on dead relatives. But they could also be purloined from the living, as the police do with suspects. The law views such DNA as "abandoned."
"If you won’t give me your DNA but I run after your cigarette butt and I don’t contaminate it, can we get your DNA?" said Bennett Greenspan, president of Family Tree DNA, which nearly doubled its kit sales last year. "The answer is yes."
But that does not mean genetic genealogy companies want to encourage the practice.
Mr. Greenspan invited a bioethicist to speak at the company’s third annual genetic genealogy conference in Houston last fall. "Don’t do anything you wouldn’t do in broad daylight," the speaker told the audience.
The message did not resonate, according to several attendees.
"We’re all like, ‘I’d pick up the cup in broad daylight,’ " one recalled.
For now, genetic genealogists are striking their own ethical balance.
Rebekah Lloyd, 53, of Denver wrestles with her conscience as she plots to visit an 86-year-old aunt, who has dementia. "I feel a little like a DNA vampire," Ms. Lloyd said. But her aunt’s cells, Ms. Lloyd believes, may hold crucial confirmation of her own American Indian ancestry.
Bob Grieve, 55, stores a DNA kit in his refrigerator to use upon his father’s death.
After testing his own DNA at the request of a distant cousin, Mr. Grieve was shaken to discover that he did not match any of his extended family, including his first cousin, the son of his father’s brother.
That could only mean an occurrence of what genetic genealogists call a "nonpaternal event." Either his father was not his father, or his grandfather was not his father’s father. But the elder Mr. Grieve has refused to surrender to the swab.
"I don’t put blame on anybody," said Mr. Grieve, an engine design checker in Dearborn, Mich. "It would just be nice to know where I came from."
Roberta Estes, for her part, is contemplating exhumation. After three decades researching the Estes family tree, and recruiting 70 Esteses for DNA testing, Ms. Estes found reason to question whether her father was, in fact, an Estes.
He has been dead for 43 years.
Ms. Estes, a technology consultant in Brighton, Mich., recently got a $20,000 estimate for digging him up.