Police Could Use DNA to Learn the Color of Suspects' Eyes

By Veronique Greenwood | December 13, 2011 4:37 pm


In the dreams of crime scene investigators, no doubt, they can feed a piece of hair into a machine and see a reconstruction of what the owner looks like. There’s a hint of that fantasy in the news that Dutch scientists have developed a test intended help police tell from a crime scene DNA sample the color of a suspect’s eyes. This information is gleaned from examining six single nucleotide polymorphisms, small genetic markers that are used in DNA fingerprinting, and could potentially help steer investigations when there are few other leads on a suspect and there is no match in police DNA databases. But the test, which can tell whether someone has blue, brown, or indeterminate (which encompasses green, hazel, grey, etc.) eyes with an average of 94% accuracy, doesn’t seem to have been tested outside of Europe, which raises questions about how well it would work in populations with greater diversity. It’s also a little hard to feature how you could bring this information to bear in a vacuum of other details—you’d want to avoid hauling someone in just because they looked suspicious and have the same eye color as the readout for the perp. At the moment, the test is not accurate enough to be introduced as evidence in court, which could be a bad thing or a good thing…depending on how many Philip K. Dick novels you’ve read.

Image courtesy of wetwebwork / flickr

CATEGORIZED UNDER: Living World, Technology
  • Jockaira

    This eye-color test could be of great value in the elimination of suspects which would translate to a better allocation of investigatory resources. It could also be used defensively in court, but with a 94% efficacy, it would usually still be only strong circumstancial evidence and would need corroborating evidences except for disqualifying eye-witness evidence based in large part on eye color.

    When the test’s accuracy approaches or arrives at 100%, it will then only serve mainly as negative evidence which is better than a poke in the eye with a sharp stick.

  • Smarti

    Criminals with even a modicum of brains will wear colored contacts which will definitely be easier than altering their fingerprints!

  • MrsG

    It will be prohibitively expensive to restest all the felons in the national databases for eye color. The databases are used for searching the evidence on an “unknown suspect” case. SNP testing would take huge chunks of time and money. The labs are already severly backlogged. I love it when non-forensic folks come up with these ideas and then say the labs can produce this type of work! Local & state government labs can outsource this work and the money comes from Federal sources in the form of grants. Are you willing to throw the country into further debt to SNP test millions for eye color?

  • TheCritic

    I agree, but just wanting to reiterate that 94%, from a strict statistics standpoint, is an insignificant percentage. You could read that as having a 6% chance of a random person having the same eye color as the perpetrator, which for a test such as this, would be reckless to use with such an inaccuracy. So, I agree, better to wait til it’s 99.5% or better.

  • B.E. Henriksen

    Clone and arrest :S

  • Jockaira

    TheCritic’s right. Any thoughtful juryperson, prosecutor, or even defense attorney would lend little credence to a 94% probability, which puts it into the same category as “maybe.”


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