Host Ira Glass surveys the effects DNA has had on the criminal justice landscape. He talks with Huy Dao, at the Innocence Project, where they are waist-deep in 2,000 letters from prisoners claiming DNA can prove them innocent. Charlotte Word at Cellmark Diagnostics, the largest and oldest private DNA forensics lab in the country, explains how their caseload is expanding into all sorts of new areas like insurance claims and medical malpractice suits. John Stanton, a detective in Arlington, Texas, recently opened up over 49 old unsolved cases, to see if DNA might be successful where old methods weren't. One case he reopened: The very first case he went on himself as a young crime scene officer in 1985. And finally, Chicago Tribune investigative reporter Maurice Possley explains that DNA has shed so much doubt on the criminal justice system in Illinois that now prosecutors and judges are reopening questionable cases that don't even have DNA evidence. (6 minutes)