Slashdot Mirror
Building the Face of a Criminal From DNA
Dave Knott writes: It sounds like science fiction, but revealing the face of a criminal based on their genes may be closer than we think. In a process known as molecular photo fitting, scientists are experimenting with using genetic markers from DNA to build up a picture of an offender's face. Dr. Peter Claes, a medical imaging specialist at the University of Leuven, has amassed a database of faces and corresponding DNA. Armed with this information, he is able to model how a face is constructed based on just 20 genes (this number will soon be expanded to 200). At the moment, police couldn't publish a molecular photo-fit like this and hope to catch a killer. But that's not how Dr. Claes sees the technique being used in a criminal investigation. "If I were to bring this result to an investigator, I wouldn't necessarily give him the image to broadcast. I would talk to him and say okay, you're looking for a woman, with a very specific chin and eyebrow structure."
I like how he talks about how he would envision seeing this used, but, I think he actually has it backwards. Not surprizing since, his expertise is in the technique, not necessarily in what it may be used for.
Rather than "you are looking for...." better is to hold this back and narrow down the field. "You have X suspects, now you can eliminate all that don't match this". That will give you better results than "look for people who match this".
This sort of thing has come up many times with the use of this sort of statistic. There are only a handful of blood types, for example, but, if you can say with certainty that the suspect is one of a small group of 2 or 3 people, then blood type might get you down to 1....even though it would be otherwise pretty useless without other information to go on.
"I opened my eyes, and everything went dark again"