ATHENS, Ohio - A new DNA analysis technique under development at Ohio University may help authorities identify the remains of victims of the 9/11 terrorist attacks when conventional tests don't work. The method could offer forensic scientists a new tool to examine badly degraded remains - such as those at the World Trade Center disaster site - and could help police name perpetrators of crimes.
With a $453,000 grant from the U.S. Department of Justice, scientist Bruce McCord is developing a set of new DNA markers for damaged human remains that can't be identified with the U.S. government's current protocol for deaths and missing person cases. Fire, major accidents and exposure to the elements can deteriorate remains, making it difficult for authorities to distinguish the dead -- even with conventional DNA analysis techniques, said the researcher, who is leading the project with collaboration from the federal National Institutes of Standards and Technologies, a physical science research laboratory.
McCord, a former Federal Bureau of Investigation scientist, began work on the new method last year, but found an unexpected opportunity to test the science in the months after the 9/11 terrorist attacks, when authorities struggled to distinguish the remains of the victims of the World Trade Center disaster. Though McCord and his research team have not worked directly with those remains, in January his partners at NIST sent the test kits to authorities in New York, where the technique has been used successfully to help match DNA remnants to missing people.
"We're very happy we've been able to help out in a small way," said McCord, an assistant professor of chemistry and biochemistry at Ohio University.
Identifying victims of disasters or missing persons is only one possible use for the new method. The technique holds promise for matching DNA from blood, hair and semen samples at crime scenes to offenders in a national database, McCord said. As felons tend to repeat their crimes, developing profiles of convicted criminals could aid law enforcement in solving cases across the country, he added.
When law enforcement authorities find blood, bone or other human tissue at a crime site, the sample is taken to a laboratory, where scientists chemically break down the matter to isolate DNA. Next, forensic scientists look for the absence or presence of certain DNA markers on the chromosomes, including repeated sequences of DNA. These patterns of these sequences - which researchers have dubbed "genetic stutter" or "junk DNA" - are used to identify individuals, and so are invaluable to the forensic chemist, McCord said.
But factors such as fire, an airplane crash or prolonged exposure to the elements can break down the DNA in a human body into very small fragments - so small that they won't hold up in the standard DNA typing test used by government authorities, which examines a suite of 13 key genetic markers. Scientists have turned to a technique called mitochondrial DNA typing as a back up, but it provides results that don't match the national database of DNA profiles of criminal offenders, McCord said.
"It's not very informative," he said. "It's kind of a last-resort alternative."
To try to solve this problem, McCord and his colleagues are developing a smaller set of reliable DNA markers called a "miniplex" that forensic scientists can use to study tiny pieces of genetic material. The technique, which the research team has tested on blood and bone samples, already has provided good results in the laboratory and has been utilized in the World Trade Center investigation.
McCord expects that several more years of research will be required, however, before the technique is ready for more extensive use on criminal cases. The researchers will explore how degraded a sample can be for the process to work, what factors - such as soil contaminants or compounds in the blood - reduce the efficiency of the technique and other questions.
McCord's collaborators on the project include John Butler, a research scientist with NIST; Nancy Tatarek, an assistant professor of anthropology at Ohio University; former post-doctoral student Yin Shen, graduate student Denise Chung and undergraduate student Kerry Opel, all of Ohio University.
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