A MURDER has been committed, and all the cops have to go on is a trace of DNA left at the scene. It doesn't match any profile in databases of known criminals, and the trail goes cold. But what if the police could issue a wanted poster based on a realistic "photofit" likeness built from that DNA? Not if, but when, claim researchers who have developed a method for determining how our genes influence facial shape. One day, the technique may even allow us to gaze into the faces of extinct human-like species that interbred with our own ancestors. It's...