Forensic scientists have devised a test that examines blood samples left at crime scenes to predict the age of crime suspects to within four years. The test could help police narrow down their search for perpetrators in cases where they do not have an exact DNA match for samples found at crime scenes. Jim Drury met the lead researcher.
DNA left by suspects at a crime scene often won't result in a match. But new forensic tests on blood and teeth samples can predict a perpetrator's age to within four years and could help police narrow their hunt. SOUNDBITE (English) BRAM BEKAERT, LEAD RESEARCHER IN DNA TEST, UNIVERSITY OF LEUVEN, SAYING: "The blood test, for example, has an accuracy of about 3.75 years over a whole age population, meaning that from newborns up to about 91 years of age our accuracy was about 3.75." The Leuven University team tested four age-associated DNA methylation markers against hundreds of blood samples of individuals whose age was known. SOUNDBITE (English) BRAM BEKAERT, LEAD RESEARCHER IN DNA TEST, SAYING: "Some chemicals at specific positions in our DNA actually increase or decrease with age, and we use the most significant positions to put them into a single test and use that on forensic samples....the younger the individual is the higher the accuracy is because it has had less influence of the environment....So the error rate for younger people is about two years of age." Teeth sample tests predicted individual ages with an error margin of 4.86 years. Pinpointing a suspect's age range should help police rule out large sections of a population, and potentially many prime suspects. The tests could also be used in 'cold cases' where police have ceased active investigation. Police departments in various countries have shown interest.