Monday, January 14, 2013
The Identitas v1 Forensic Chip allows investigators to home in on someone's gender, eye and hair color, as well as ancestry - all based on a small sample of DNA such as that from saliva on a cigarette butt
Developed by VisiGen, a consortium of universities and law enforcement agencies, the chip is the first to provide data on all these traits simultaneously. Other devices can determine at most two at a time - usually eye and hair color. The new chip contains hundreds of thousands of short sequences of DNA that bind to different single nucleotide polymorphisms (SNPs) - single letter variations in the genetic sequence - in the DNA sample. SNPs are indicative of physical traits, so once we know which SNPs are present in the sample, software can be used to compute likely appearance and ancestry. The VisiGen team tested the chip on more than 3000 DNA samples collected around the world, and found that it was 99% accurate at predicting gender. The chip also predicted European or East Asian ancestry with an accuracy of 97%, and African ancestry in 88% of cases. However, it was only 63% accurate at predicting blond hair.