National Geographic : 2016 Jul
Beyond reasonable doubt 35 geographic ancestry, eye and natural hair col- or, and even a possible shape for facial features. Quaal immediately thought of the Bouzigard case, in which the DNA left at the scene was virtually the only lead. She contacted Mancuso and Lt. Les Blanchard, a detective on the case, and they sent their sample to Ellen Greytak, di- rector of bioinformatics at Parabon NanoLabs, a company specializing in DNA phenotyping. Here the investigation took an unexpected turn. Based on the available evidence, the detec- tives still believed her killer was likely Hispanic— perhaps a member of the Mexican crew who had fled the area soon after committing the crime. But the person in the DNA-generated portrait Parabon produced had pale skin and freckles. His hair was brown, and his eyes were probably green or blue. His ancestry, the analysis said, was northern European. “We kind ofhad to take a step back and say all this time, we’re not even in the right direc- tion,” Mancuso says. But armed with this new evidence, he is optimistic. “I think at some point we can solve this case, because we have such a good DNA sample and this profile,” he says. “ We know who the killer is. We just don’t know who the killer is.” DNA phenotyping is a relatively recent arrival Fingernails can catch a murderer. Medical examiners clip a victim’s nails to see if DNA from tissue trapped under them during an attack matches a sample in the DNA database. Even without a match, a new technique known as DNA phenotyping can reveal the assailant’s eye, skin, and hair color—or even suggest the outlines of a face.