Forensic DNA databases are a potentially powerful law enforcement tool, but may disproportionately target poor and dark-skinned wrongdoers, biotechnologically magnifying flaws in criminal justice systems.

“Forensic DNA databases are growing to mirror racial disparities in arrest practices and incarceration rates,” write sociologists Troy Duster and Peter Chow-White in an Oct. 4 Public Library of Science Medicine essay.

In the last decade, as DNA became the gold standard of forensic evidence, DNA collection by law enforcers became routine. At least 56 countries have a national DNA database. In the United States, the FBI’s database contains 5 million profiles, and DNA is also gathered at state and local levels, where a patchwork of laws govern how it’s collected and managed. Some states gather DNA from anyone arrested for a felony, or use so-called “DNA dragnets” to gather samples from anyone in geographical proximity to a crime. And samples may be kept indefinitely, even if suspects are cleared of charges.

Civil rights advocates have warned that demographically unbalanced forensic DNA data banks could “create a feedback loop.” Because samples are stored and compared against DNA collected at future crime scenes, police will be more likely to pursue crimes committed by members of overrepresented groups, while underrepresented groups can more easily evade detection.

The potential for problems expands when states permit so-called familial DNA searches, in which police who can’t find a database match to crime scene DNA can search the database for partial matches, ostensibly from the suspect’s family and relatives, who can then be targeted. It’s even possible to imagine situations in which some races or groups become universally covered, while others remain only partially surveyed.

According to Duster and Chow-White, this represents a biotechnological aspect of the “digital divide,” a term better known from debates in the 1990s, meaning that the internet’s benefits could be unfairly distributed. It might sound strange in this context, but “DNA technology is information technology,” said Chow-White. “DNA is closely tied to our analog ideas of biology, to blood and kin. But when DNA turns into digital code, much like when our lives turn into digital code,” the consequences become social and networked.

Ironically, the overrepresentation of minorities in forensic DNA databases has occurred even as they’ve become underrepresented in medical genetics research, said Chow-White and Duster.

As for criminal justice, the solutions aren’t clear. Some people have advocated taking DNA from everyone. Others say a universal database violates Fourth Amendment protections against unreasonable searches and betrays the principle of presumed innocence.

Duster and Chow-White have no prescription, but “the first and foremost step in addressing the problem is recognizing that this is an issue,” they write. “We cannot address the problem unless or until there is awareness.”

Image: James Cridland/Flickr

Citation: “Do Health and Forensic DNA Databases Increase Racial Disparities?” By Peter Chow-White and Troy Duster. PLoS Medicine, Vol. 8 No. 10, October 4, 2011

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