So I’m catching up on news items, and –oh my gosh! did you see this? From the L.A. Times: How reliable is DNA in identifying suspects?.
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.
In the years after her 2001 discovery, Troyer found dozens of similar matches — each seeming to defy impossible odds.
As word spread, these findings by a little-known lab worker raised questions about the accuracy of the FBI’s DNA statistics and ignited a legal fight over whether the nation’s genetic databases ought to be opened to wider scrutiny.
The FBI laboratory, which administers the national DNA database system, tried to stop distribution of Troyer’s results and began an aggressive behind-the-scenes campaign to block similar searches elsewhere, even those ordered by courts, a Times investigation found. [continue]
DNA is accurate: but, like fingerprints, it may often be used in law enforcement based on a too-small portion/base of data. Fingerprints, for example, are not considered conclusive by scientists without [I think] at least 16 correspondances but in court experts [technicians – knowledgeable but held to a different standard standard] may use 7.