New CSI Tool: A DNA Test That Predicts Hair and Eye Color

Future Tense
The Citizen's Guide to the Future
Aug. 28 2012 1:54 PM

New CSI Tool: A DNA Test That Predicts Hair and Eye Color

DNA samples from a crime scene could help police predict a suspect's hair and eye color.
DNA samples from a crime scene could help police predict a suspect's hair and eye color.

Photo by Mario Villafuerte/Getty Images

“Forensic evidence” has an authoritative sound to it, like the click of a (brief) case closing. But until recently, trace DNA left at a crime scene got police nowhere unless they could match it to samples already in their database.

A new technique, Forensic DNA Phenotyping, allows investigators to predict suspects’ hair and eye color by analyzing stand-alone DNA evidence. This is especially useful in situations where little is known about the alleged offender and the pool of possible culprits is wide.   

Advertisement

The HIrisPlex system relies on 24 eye- and hair-color-predictive DNA variants, including six genetic markers used to estimate eye color in an earlier test. Using HIrisPlex, scientists were able to predict blonde hair with 69.5 percent accuracy, brown hair with 78.5 percent accuracy, red hair with 80 percent accuracy, and black hair with 87.5 percent accuracy. (Might the takeaway here be that blondes are more likely to get away with murder?)

They were also able to distinguish, 86 percent of the time, between brown-eyed, black-haired people of European and non-European origin. And after analyzing DNA samples from populations around the world, they concluded that a person’s geographic ancestry did not affect the test results.

No doubt these are some encouraging developments for CSI types. Still, criminals are bound to figure out sooner or later that they can hit back at HIrisPlex by dying their hair or wearing tinted contacts.

Future Tense is a partnership of SlateNew America, and Arizona State University.

Katy Waldman is a Slate staff writer. 

TODAY IN SLATE

Technocracy

Forget Oculus Rift

This $25 cardboard box turns your phone into an incredibly fun virtual reality experience.

The Congressional Republican Digging Through Scientists’ Grant Proposals

The 2014 Kansas City Royals Show the Value of Building a Mediocre Baseball Team

The GOP Won’t Win Any Black Votes With Its New “Willie Horton” Ad

Whole Foods Is Desperate for Customers to Feel Warm and Fuzzy Again

The XX Factor

I’m 25. I Have $250.03.

My doctors want me to freeze my eggs.

The XX Factor
Oct. 20 2014 6:17 PM I’m 25. I Have $250.03. My doctors want me to freeze my eggs.
Politics

Smash and Grab

Will competitive Senate contests in Kansas and South Dakota lead to more late-breaking races in future elections?

I Am 25. I Don’t Work at Facebook. My Doctors Want Me to Freeze My Eggs.

These Companies in Japan Are More Than 1,000 Years Old

  News & Politics
The World
Oct. 21 2014 11:40 AM The U.S. Has Spent $7 Billion Fighting the War on Drugs in Afghanistan. It Hasn’t Worked. 
  Business
Moneybox
Oct. 21 2014 1:12 PM The Global Millionaires Club Is Booming and Losing Its Exclusivity
  Life
The Vault
Oct. 21 2014 2:23 PM A Data-Packed Map of American Immigration in 1903
  Double X
The XX Factor
Oct. 21 2014 1:12 PM George Tiller’s Murderer Threatens Another Abortion Provider, Claims Right of Free Speech
  Slate Plus
Behind the Scenes
Oct. 21 2014 1:02 PM Where Are Slate Plus Members From? This Weird Cartogram Explains. A weird-looking cartogram of Slate Plus memberships by state.
  Arts
Brow Beat
Oct. 21 2014 1:47 PM The Best Way to Fry an Egg
  Technology
Technology
Oct. 21 2014 10:43 AM Social Networking Didn’t Start at Harvard It really began at a girls’ reform school.
  Health & Science
Climate Desk
Oct. 21 2014 11:53 AM Taking Research for Granted Texas Republican Lamar Smith continues his crusade against independence in science.
  Sports
Sports Nut
Oct. 20 2014 5:09 PM Keepaway, on Three. Ready—Break! On his record-breaking touchdown pass, Peyton Manning couldn’t even leave the celebration to chance.