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As DNA Databases Grow, Uses Grow Too

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As DNA Databases Grow, Uses Grow Too


As DNA Databases Grow, Uses Grow Too

As DNA Databases Grow, Uses Grow Too

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Here's a scenario: police take a blood sample from a crime scene. They compare the DNA to that of convicted criminals, but get no match. But they find someone with similar DNA, and that leads them to a relative of the near match. DNA databases are growing rapidly and could be used to cast a wider DNA surveillance net than anyone ever expected.


The U.S. Government has DNA information on nearly three million people who've been convicted of a crime. Police commonly compare DNA from a crime scene with that database to find suspects. Sometimes they don't get a perfect match but a very close one. A DNA profile that could belong to a relative of the convicted person in the database. As NPR's Christopher Joyce reports, that's created a heated debate.


Here's a true story. A young girl was murdered. The killer left blood and DNA at the crime scene. Police compared it to a DNA library of convicted people but there was no exact match. They did find some near matches though. Harvard University's Frederick Bieber, a medical geneticist tells what happened next.

Dr. FREDERICK BIEBER (Geneticist, Harvard University): And they looked at the profile that was most similar to the crime scene evidence overall, wasn't a perfect match, but it turned out to have come from a 14-year-old boy who had gotten into the database for a minor traffic infraction.

JOYCE: Authorities realized the crime scene DNA probably came from someone closely related to that 14-year-old.

Dr. BIEBER: And it turns out they eliminated his father but it was his uncle who had a perfect match to the crime scene evidence. And he later confessed and was convicted.

JOYCE: This happened in Great Britain where a so-called familial searching is routine. Now here's another true crime story. There's a rape in Virginia. Police compared the crime scene DNA to the state's DNA database. They got a near match. A fuzzy hit as it's sometimes called, to a convicted felon. They, too, realized that the unknown rapist might well be a close relative of that known felon. Paul Ferrara, head of forensic sciences for Virginia, says he's unhappy about what happened next.

Mr. PAUL FERRARA (Director, Virginia Division of Forensic Sciences): We decided that we should not report that information to the police.

JOYCE: How did you feel about that?

Mr. FERRARA: Pretty lousy. Still bothers me.

JOYCE: Ferrara couldn't report it because Virginia has decided familial searching might be unethical. There are no federal rules against familial searching but Ferrara says some people don't like the idea of having a close relative's DNA in a database in effect makes their own DNA traceable.

Ferrara says he'd like to change the rules but he also doesn't want to jeopardize public faith in DNA databases, which not only help, convict criminals but sometimes exonerate those wrongly convicted.

Ferrara says he gets a fuzzy hit once or twice a year, but the U.S. Government's database keeps growing. Besides convicted criminals, some states now add people arrested but not yet tried.

Mr. FERRARA: I mean these databases are going to increase in size and the situations of familial searches that indirectly point to a relative of somebody in the database. Those situations are going to increase.

JOYCE: That doesn't bother Chris Asplen, a former federal prosecutor and a consultant on DNA forensics.

Mr. CHRIS ASPLEN (DNA consultant, former federal prosecutor): On any scenario, you're going get people, innocent individuals who are caught up in the investigative dynamic. DNA doesn't make that any different other than DNA has a greater ability to exonerate those innocent people faster and with significantly greater certainty than we could ever do before.

JOYCE: But Harvard's Frederick Bieber says there are lots of DNA databases springing up. Families of the victims of the World Trade Center bombing and Hurricane Katrina gave DNA to authorities for example. Sometimes police take DNA from men during rape investigations to eliminate possible suspects. Rules vary on what happens to that information after the cases are closed.

Dr. BIEBER: The concern that some have, of course, is that once a DNA sample is collected and retained by any agency, all one would need would be a change in statute to allow such testing. It would put larger groups of people potentially under lifelong genetic surveillance because they happen to be related to somebody who's in the criminal justice system.

JOYCE: Bieber writes about the debate in the latest issue of the journal Science hoping, he says, to stimulate wider debate. Christopher Joyce, NPR News.

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