Forensic DNA has become a law enforcement staple, making much of the guesswork and old-fashioned "detecting" unnecessary, even obsolete. It's become so widely accepted that it's even spawned its own brand of crime shows like CSI (Crime Scene Investigators). However, there is a muddy and unpredictable side to DNA testing, and it has nothing to do with the test's results. Instead, the FBI's national genetic databank has been building a storage base of 5 million profiles based on stored DNA samples. Almost all of these DNA samples are from previous persons of interest in a criminal justice case, with their particular DNA stored away for future cases. Seems like sound logic, but it's actually having some unintended consequences.

When the FBI or local law enforcement investigate a crime scene, collecting possible DNA samples is part of the regular police work. Those samples are screened against all 5 million profiles currently in our national DNA database, looking for a match to open up possible leads or persons of interest. However, after over a decade of building this database, the profiles of poor and minority individuals are vastly over-represented, just as they are in criminal courts and prisons (even though they’re vastly underrepresented in medical DNA records). The argument of crime and the culture of poverty notwithstanding, as Brandon Keim of Wired.com noted, “Civil rights advocates have warned that demographically unbalanced forensic DNA data banks could create a feedback loop.” In other words, when police are more likely to pursue leads from the over-represented groups within the DNA databank, whereas criminal leads from underrepresented groups are much less likely to be detected. As police become increasingly reliant on DNA “Dragnets” to connect the dots, people not within that databank are much less likely to end up on law enforcement’s radar.

Even more problematic are “familiar DNA searches” in which partial DNA matches in the databanks can be pursued as possible leads within the case. This widens the net in many of these over-represented groups by inputting even more DNA profiles of a particular background into the databank for future searches. The ultimate result, as Keim related, “it’s possible to imagine situations in which some races or groups become universally covered, while others remain only partially surveyed.”

There have been a number of attempts by both law enforcement and civil rights groups to correct, or at least increase awareness of the incredibly unbalanced DNA dataset within our national database. Some groups have advocated simply collecting DNA from everyone (as simply as a check swab at birth), but constitutionally it violates fourth amendment rights and, others argue still, it infringes upon the presumption of innocence in a court of law.