DNA sample may be enough to build an image of your face

Derek Todd Lee: genetic analysis of DNA evidence found at the crime scene helped lead to his arrest

DICK AHLSTROM, Science Editor, in Chicago

FORENSIC SCIENCE is about to take a startling new turn – reconstructing facial features and skin tone simply by reading your DNA. This goes far beyond doing an identity-proving genetic fingerprint, it means the person’s actual face will emerge after analysing a collection of genes, according to a scientist from Pennsylvania State University.

The process, “forensic molecular photofitting” relies on mapping genes that are linked to skin pigmentation and in its more complex form, to groups of genes that control facial structure, stated Dr Mark Shriver.

The approach has already been used to help identify and convict a serial killer in Baton Rouge, Louisiana, Dr Shriver said over the weekend at a presentation to the American Association for the Advancement of Science annual meeting in Chicago.

The session was chaired by Ireland’s chief scientific adviser, Prof Patrick Cunningham.

Derek Todd Lee was convicted of murder in 2004 and faces a death sentence. He is implicated in the deaths of at least seven women. Initial witness testimony indicated he was white, but genetic analysis of DNA evidence left at the crime scenes showed he was actually African American, something that aided his arrest, Dr Shriver said.

He has done extensive analysis of the genetic origins of Americans, looking for DNA markers to indicate the mix of European, African or Native American background.

“We are not doing race genetics,” he said. Race was a complex issue that involved both cultural and biological aspects. “Race is a mixed effect and its meaning is interpreted in different ways.” Rather, he was trying to understand population genetics as applied generally in molecular biology.

Work so far showed the European American/African American genetic mix was as low as 3.5 per cent in a sample from Georgia but as high as 35 per cent in a sample from Seattle.

Dr Shriver is now mapping genes that define facial shape. He links the gene mix with fixed points on the face, for example eye corners and separation, corners of the mouth, nose tip and length and face edges.

These are being computerised with the gene mix indicating what the ratio will be between these various facial features. It allows the computer to build up an image of a face based only on the gene mix found in the DNA. He indicated that “maybe 500 facial markers and 500 ancestry markers” would be enough to build an accurate and complete face.