The Problems with Arizona's DNA Database

FBI resists scrutiny of 'matches'

DNA: GENES AS EVIDENCE A crime lab's findings raise doubts about the reliability of genetic profiles. The bureau pushes back.

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.  Read more . .