DNA yields victims' elusive IDs


Forensics: Laboratories look inside human cells to identify remains found in the debris of New York's World Trade Center.

November 18, 2001|By Michael Stroh | Michael Stroh,SUN STAFF

SPRINGFIELD, Va. - On their long journey home from the World Trade Center, some of the dead pass through an unusual way station: Mark Radcliff's freezer.

Radcliff is an evidence custodian at Bode Technology Group, one of three private laboratories hired by New York City to help identify its dead. His job: making sure chunks of bone, tufts of hair and vials of victim DNA chilling behind locked doors find their way to scientists trying to attach names to them.

Seemingly forgotten amid worries of anthrax and Afghanistan are the many forensic scientists quietly plugging away on the largest DNA identification effort in history. Of the 3,554 officially missing from the World Trade Center - a number constantly in flux - 589 bodies have been identified, according to New York officials. Most were done the old-fashioned way: through dental records, tattoos, birthmarks, old X-rays and, when investigators got lucky, a driver's license in a back pocket.

But with the easy cases mostly in the past and thousands of anonymous human fragments piling up (more than 9,500 at last count), a fragile filament of deoxyribonucleic acid - the molecular blueprint of life that makes each human unique - might be the only hope many families have left.

Two months after the terrorist attacks, DNA is finally starting to yield results, putting names to 32 victims, according to city officials. But it's slow going. Most of the human remains emerging from the World Trade Center site are little but hair and bone, much of it badly scorched. Scientists at Bode have been able to pluck useful DNA data from only about half the samples. In the end, it might be up to Celera Genomics in Rockville to crack the hardest cases using an alternative DNA identification method. But even that technique, in the absence of other evidence, could leave lasting mysteries.

"It's frustrating," says Mitchell Holland, the forensic scientist heading Bode's World Trade Center effort. "We know the families are grieving and how much this means to them. Every sample we can't identify is painful."

DNA has been a key part of the forensic science tool kit since 1987. Used originally to catch criminals, it is now also important for bringing closure.

DNA helped investigators identify all 230 victims of TWA Flight 800, which crashed off Long Island in 1996. It's putting a face on skeletons dug up in the killing fields of Bosnia. It has reunited the remains of hundreds of U.S. soldiers killed in Korea and Vietnam with their families. In 1998, DNA solved the riddle of which Vietnam soldier lay in the Tomb of the Unknowns.

"A DNA profile is like a Social Security number," says Holland. "It's unique."

It can also be surprisingly durable. Sheltered inside bone or enamel-coated teeth, DNA has been plucked intact from a 100,000-year-old Neanderthal man and skeletons submerged for months at the bottom of the Atlantic Ocean. But even DNA identification has its limits, and forensic experts say the World Trade Center case is likely to push them.

Situated in a bland suburban office park, Bode is one of the largest private forensic labs in the country. On a typical day its scientists are busy processing DNA from rape and murder cases, or helping states such as Maryland clear backlogged criminal DNA databases, says Thomas Bode, the company's president.

But two freezers that once contained evidence from crime scenes are now packed with 4,375 bones and other remains from New York, each tagged with a bar code. Some arrived by Federal Express; others were chauffeured by New York officials with a police escort. Once, Radcliff, a 35-year-old Baltimore County resident, drove to Manhattan to retrieve 19 boxes of bones.

"The main thing on my mind was not having any kind of accident," he says of that trip. "I want the families to have closure."

To identify the remains, Bode scientists are using a standard forensic technique known as short tandem repeat (STR) analysis, which involves decoding 13 regions of DNA extracted from a cell's nucleus. These 13 locations were chosen because they vary widely among people, so the chance that the technique could lead to a false match is less than one in a trillion.

Scientists start by shaving a bit of bone and soaking it in chemicals to unlock the DNA inside. The DNA is then fed through automated gene analyzers to read its string of chemicals. Two of the machines, which look a bit like drugstore film processors, have playfully been given the Star Wars nicknames Jabba and Boba Fett.

Once processed, each sample's DNA profile is burned onto a compact disc and sent to the New York State Police Forensic Laboratory in Albany, where it joins DNA results from Myriad Genetics in Salt Lake City, another lab doing DNA work on World Trade Center remains.

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