Bearing hairbrushes, drinking glasses, chewing gum and electric razors once used by victims of the World Trade Center collapse, families by the hundreds have begun helping New York authorities with the largest forensic DNA identification project in history.
Analyzing up to 500,000 tissue samples and body parts expected to come from the rubble could take millions of hours of laboratory work, experts said. The nationwide effort is comparable in scale to the decadelong Human Genome Project.
New York City medical examiner's office said the largest private genome sequencing center, Celera Genomics Group, has been enlisted to help with the toughest cases, in which technicians have no reference DNA from the victim and must identify tissue by comparing it with DNA taken from cheek swabs from his or her relatives.
Although genetic evidence is not usually relied on for identification because the analysis is costly and time-consuming, experts said the grisly disaster scene in lower Manhattan requires unprecedented measures. DNA may be the only hope of identifying thousands of bodies burned by jet fuel and crushed under a half-million tons of falling skyscrapers.
New York officials said family members wishing to provide DNA samples for comparison should contact LabCorp, a diagnostics company with more than 900 service centers nationwide, including several in the Chicago area. LabCorp officials said in the last four days they have received three inquiries from the Chicago area about submitting tissue samples.
The national network of DNA sample collection will "probably set a precedent for future investigations," Dr. Edmund Donoghue, the Cook County medical examiner, said.
In New York on Tuesday, relatives of the missing walked into a collection center along the Hudson River clutching little shopping bags. Inside were personal items--including underwear and cigarette butts--that could yield DNA samples and give family members answers to the painful question of their loved ones' fates.
Stephen Dorf contributed a sample of his saliva along with a toothbrush and a hairbrush that belonged to his brother Robert, who worked on the 84th floor of one of the towers.
"The more DNA they have, the better they can identify the people," Dorf said.
At the New York medical examiner's facility at 1st Avenue and 30th Street--the largest forensics laboratory in the country--hundreds of specialists have been sorting through tissue from ground zero, working no longer than three hours at a time to avoid being overwhelmed by the grim task. Psychologists and chaplains are on hand to console the technicians and the victims' families.
Few DNA forensics projects have approached the size or complexity of the job in New York. Natural disasters such as earthquakes often leave the victims' bodies largely intact. Passenger lists make it easier to identify the victims of most airplane accidents, which also often leave small crash sites.
One of the few comparable efforts is in Bosnia, where experts have used DNA to help identify thousands of victims of atrocities thrown into mass graves, said Dr. Robert Kirschner, a former Cook County deputy medical examiner who led the Bosnian forensic team until 1997.
That job was especially difficult because forensics workers had to extract DNA from bones that had been in the ground for years, Kirschner said.
But even so, he said, many of the bodies were more complete than what recovery workers in New York have been finding.
"We're simply not finding whole bodies anymore," said Robert Shaler, director of New York's Forensic Biology Laboratory.
At ground zero, he said, teams are looking for "something which might have discoloration on it. It's not the same as a plane crash, where you have body parts strewn all over but things are recognizable as an arm or leg. Here, it's almost like an archaeological dig. And it's going to take time. A lot of time."
Shaler and other officials said DNA analysis probably will continue into 2002.
Sequencing company Celera will focus on the difficult task of testing mitochondrial DNA, a small part of the genetic code that can be used to match tissue samples with living relatives or to get genetic information out of hair samples.
As tissue decays in the coming weeks, the DNA will degrade, which may make the laboratory task more difficult, Shaler said. More sophisticated tests could be required that reveal an individual's genetic code in great detail.
New York also has turned to Salt Lake City-based Myriad Genetics, which recently completed sequencing the rice genome after more than two years of round-the-clock effort.
The identification project will be taxing, but not as labor-intensive as the rice genome, Myriad Genetics spokesman William A. Hockett said. "We expect a steady flow of samples," he said.
Hockett said DNA identification typically costs about $50 per sample, though no price tag has been set on the New York project. Ellen Borakove of the city medical examiner's office said state and federal funds should help offset the costs.
Considering the inevitable anguish for families as the lengthy forensics work progresses, some New Yorkers have suggested burying remains in a common memorial.
But Donoghue said it's crucial to put names to as many victims as possible. Identification makes it much easier for families to settle their loved ones' estates, make insurance claims--or, in the case of surviving spouses, to remarry.
"There are all sorts of ramifications," Donoghue said. "It gives them some closure."