My story in today’s paper, “Raising Doubt on DNA,” deals with the practice of using DNA databases and DNA found at a crime scene to identify the perpetrator. It was sparked by an ongoing series in the Los Angeles Times, especially last Sunday’s piece.

It’s an eye-opener. Last Sunday’s story begins like this:

State crime lab analyst Kathryn Troyer was running tests on Arizona’s DNA database when she stumbled across two felons with remarkably similar genetic profiles.

The men matched at nine of the 13 locations on chromosomes, or loci, commonly used to distinguish people.

The FBI estimated the odds of unrelated people sharing those genetic markers to be as remote as 1 in 113 billion. But the mug shots of the two felons suggested that they were not related: One was black, the other white.

According to the Times, “Arizona searches” in that state, Illinois and Maryland have yielded more than a thousand instances in which at least two samples match at nine or more loci. The FBI says the way the searches are conducted skews the result, and points out that it now looks for matches at 13 loci.

To read last Sunday’s story, click here; for other stories in the Times’ series, click here.

CARYN TAMBER, Legal Affairs Writer