FBI Fights Testing For False DNA Matches

Slashdot notes an article in the Los Angeles Times about the 2001 discovery by Arizona crime lab technician Kathryn Troyer of two felons with remarkably similar genetic profiles, so similar that they would be accepted in court as a match. However, one of the two was white and the other was black.

Although the FBI estimates the odds of unrelated people sharing those genetic markers as 1 in 113 billion, Troyer found dozens of similar matches.

Several scientists and legal experts want to test the accuracy of official statistics using the nearly 6 million profiles in CODIS, the national system that incorporates most state and local databases.

"DNA is terrific and nobody doubts it, but because it is so powerful, any chinks in its armor ought to be made as salient and clear as possible so jurors will not be overwhelmed by the seeming certainty of it," said David Faigman, a professor at UC Hastings College of the Law, who specializes in scientific evidence.

FBI officials argue that critics exaggerate or misunderstand the implications of Troyer's discoveries.

"I can appreciate why the FBI is worried about this," said David Kaye, an expert on science and the law at Arizona State University and former member of a national committee that studied forensic DNA. But "people's lives do ride on this evidence," he said. "It has got to be explained."

See the full story in the Los Angeles Times.