August 22, 2003

An Emphasis on Compassion

Continued from page 3

By Thea Singer

Gene Codes Forensics began incorporating SNP data into its calculations in November 2002, but the technology has not yet been approved by the State of New York's Department of Health for identification purposes. "Because no one's ever tried it before, the Department of Health wants to be absolutely sure," says Cash. "The worst case isn't that somebody doesn't get identified. The worst case is if you identify somebody based on a new technology, and then you have to tell a family you made a mistake."

In practice, M-FISys makes a Byzantine process appear straightforward. Human remains are found and catalogued, and a biologist places a small cutting from the bone or muscle into a test tube. The tube is sent to one of several labs, where biologists perform the three types of DNA analysis. The biologists then deliver the patterns of numbers and letters that they decipher to Gene Codes Forensics, and Cash and his team feed those patterns into M-FISys. The same process is applied to DNA samples from relatives and from personal effects. When an operator clicks on the M-FISys "Match Index" icon, the system compares every one of the thousands of samples to every other sample to see which ones match. The medical examiner's office won't declare a match between victim samples and a known DNA sample from, say, a toothbrush unless the likelihood of finding a similar match in the general population is less than one in 10 billion.

Existing DNA identification programs can incorporate both SNP data and short tandem repeat data into their match calculations, but not data from mitochondrial DNA analysis. "No one has ever tried to combine these three technologies before to collaboratively identify individuals," says Cash. "If I can say, 'These nine pieces go together; they're one person,' then hopefully I can also find a toothbrush that has the same DNA pattern so I can say, 'OK. Now I know that these are not only the same, but that they came from whoever used this toothbrush.'"