In recent years, scores of police departments across the U.S. have used Parabon's DNA phenotyping in an effort to crack difficult cases, according to the company's website. In Newport Beach, California, for example, police hope it will generate new leads in the 1973 sexual assault and murder of 11-year-old Linda O'Keefe, who was abducted as she walked home from summer school. Parabon's predictions about the suspect's appearance and ancestry are included at the end of #LindasStory, a string of Twitter messages that the department posted in an effort to jump-start the investigation.
Newport Beach Police Sgt. Ryan Peters says that after the images of the suspect's possible appearance were released, the department received more than 200 leads of various types, though he cautioned that not all of them might prove useful. But with a 45-year-old unsolved case, "we need to try something to keep it alive," Peters says.
Ellen McRae Greytak, Parabon's director of bioinformatics, says that Parabon first began working upon predicting appearance from DNA while vying successfully for a contract for the U.S. Department of Defense a few years ago. While other companies' proposals focused on a few traits, such as eye color, Parabon argued that with enough data, other physical characteristics could be predicted as well, she says.
To develop a basis for predictions, the company turned to approximately 15,000 to 20,000 anonymous volunteers, who provided their DNA and also filled out detailed descriptions of themselves. Some of those subjects — less than 5,000, according to Greytak — also had 3D images taken to show their facial shape as well.
The company data-mined that lode of information, and then used machine learning to figure out how to predict a person's appearance. "We take the parts of the DNA that we find are important for each trait, and put them together into a predictive model," Greytak says. "And that [model] can be applied to new data. If you put in the DNA of a new person, it will make a prediction of the traits."
When Parabon began offering the service to law enforcement agencies in 2014, it initially encountered skepticism, since the idea of predicting a person's appearance from DNA "sounds so science fiction," Greytak says. As a test, police departments sometimes sent samples of DNA from a volunteer in their offices, and asked the company to predict that person's appearance. The results were good enough to convince them to give it a try, Greytak says.
Since then, police departments across the U.S. have used Parabon's services as an investigative tool.