Massive DNA Testing

Experts: the only way to ID many victims

By Laurie Garrett | STAFF WRITER

September 16, 2001

Saying there is little chance of finding any more intact bodies in the World Trade Center wreckage, officials are gearing up for the largest forensic DNA screening operation in history, outstripped only by the decade long Human Genome Project.

The scale of the delicate, easily compromised laboratory work ahead is so enormous that the city has reached out to Celera Genomics Group, the world's largest genome company, which sequenced the entire human genome, and Applied Biosystems Group, the world's largest manufacturer of forensic laboratory equipment.

"I don't think we're going to find bodies anymore," molecular biologist Robert Shaler, director of the city's Forensic Biology Laboratory, told Newsday yesterday. "We're simply not finding whole bodies anymore."

Mayor Rudolph Giuliani, at a news briefing last night, said, "I think we have to be honest with people," preparing the families for the possibility that their loved ones either may never be recovered or be found only as DNA-matched body pieces.

Yesterday afternoon, the chief of Celera was in a planning meeting at the company's headquarters in Rockville, Md., discussing the Trade Center situation.

"Nothing has been finalized yet. But we're here in planning sessions trying to prepare right now," chief executive Craig Vetner said in a telephone interview. "This is a relatively sensitive area. We're trying to help quietly and stay behind the scenes."

Peter Bakersky, who is heading up all Federal Emergency Management Administration operations in New York, confirmed the lack of whole, or even partial, bodies in the World Trade Center debris. Bakersky, who has responded to nearly every major disaster in the country since 1988, has the bombing of the Alfred P. Murrah federal building in Oklahoma City as a reference point.

"What they're looking at, those items that are being recovered now, are pieces," Bakersky said. "Look, this is a 110-story building. We're still at the top levels. You probably are only going to find body parts, or nothing. Because of fire, of blast. When you're talking about temperatures of 2,700 degrees, what do you have? You have a cremation effect.

"As you get farther down, to the lower floors, you probably will find intact bodies. In Oklahoma City, the farther down we went, you found more intact bodies," he said. "Of course, when you say 'intact' it still doesn't mean fully intact. You still have crushed bodies" that may be dismembered."

It will be a long time before excavators can reach that level. Both Bakersky and Shaler said digging and sifting through the mountains of debris will last until year's end. DNA analysis probably will continue into 2002, they said.

The clock is ticking, Shaler said, and not only for thousands of families desperate to know whether their loved ones were killed in the terrorist attack. With each day, the DNA of the victims degrades, as does that of 10 hijackers aboard the Boeing 767s that crashed into the two towers.

All evidence must be properly tagged and processed, adhering to strict techniques that must be able to stand up in federal court. Any body or tissue samples must be identified using the FBI's Combined DNA Indexing System, Shaler said. The chain of control of that DNA evidence must be scrupulously logged and maintained lest anyone in a legal proceeding question its validity.

Some of the 600 samples that have come into the lab so far have contained enough reliable DNA to allow standard genetic analysis, which requires examination of 13 specific loci in human chromosomes in order to create a legal "DNA fingerprint."

"But once the DNA begins to degrade, you lose these [loci]," Shaler said. As the quality of samples worsens, either because of their deterioration over time or their original damaged condition, the scientists will have to use more exotic genetic typing methods.

"Another strategy is to look at mitochondrial DNA," Shaler said, referring to tiny packages of maternally inherited genetic material found separate from the chromosomes. "So our strategy is to first look for genomic DNA, and then go for mitochondrial. And if the DNA is really degraded, we may have to go down to the level of tetra-repeats or single nucleotide polymorphisms."

In other words, the lab is preparing to perform types of DNA analysis that would challenge even a top research laboratory. To perform this sort of very specific, difficult analysis on a massive scale, Shaler said, the medical examiner's office is reaching out to Celera, Applied Biosystems Group in Foster City, Calif., and the DNA company Myriad Genetics Inc. of Salt Lake City.

"The volume we're talking about is astronomical," Shaler said. "If you figure 5,000 people were in there, that's probably about 500,000 pieces and degraded samples we're going to get. Extracting the samples takes about two hours. Finding the DNA takes about three hours. Amplifying the DNA takes another three hours. And STR [short tandem repeat] DNA analysis takes two hours."

That makes for lab time of 10 hours per sample. With a half-million samples, that necessitates 5 million hours of labor and processing.

At the news briefing, the city asked that families provide DNA samples immediately and announced that Laboratory Corporation of America, also known as LabCorp, with facilities nationwide, will accept samples from relatives of the missing.

"DNA evidence offers us the best opportunity to help families find their loved ones," Giuliani said in the statement. "I strongly urge everyone who is missing a relative to participate in this process."

Shaler said the lab has plenty of skilled personnel, although laboratories all over the world have offered their assistance. The work is so upsetting - even gruesome - that the scientists are working only three-hour rotations.

At ground zero, teams are looking for "something which might have discoloration on it," Shaler said. "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."

This week's rain and cooler temperatures pushed FEMA's planners to think about winter conditions at the site. From Shaler's point of view, an early winter would be a good thing, as DNA samples generally remain intact longer in very cold conditions. Those same conditions, however, will make excavation even tougher, Bakersky said.