Scientists from Netherlands can now tell the age of a person from a drop of blood, a discovery that is bound to revolutionize crime scene investigation in future.

According to the study published in the journal Current Biology, experts can identify the age of unknown persons through the study of T cells, a group of immune cells in the blood. These cells identify foreign organisms entering the body, like virus and bacteria, and produce circular DNA molecules at each sighting. As the person ages, these molecules known as joint TCR excision circles reduce in numbers. Researchers analyzed these molecules to accurately derive the age of the person.

"Conventional DNA profiling applied in forensics can only identify persons already known to the investigating bodies," Dr Manfred Kayser of the Erasmus MC University Medical Center Rotterdam said. “Hence, every forensic lab is confronted with cases where the DNA profile obtained from the evidence material does not match that of any known suspect tested, or anybody in the criminal DNA database. In such cases, it is expected that appearance information estimated from evidence material will help in finding unknown persons."

When there is not enough physical evidence present in the crime scene, investigators were turning to DNA profiling to crack down these crimes. But, the science of identifying a person's color and height from their DNA profiling is still in the nascent stage to accurately portray the person in question.

Dr. Kayser, the lead researcher considers his team's method as the most accurate and reliable method of all. He says that this method with an error range of plus or minus 9 years can help the investigators in generational categorization.

He also says that this method can be put into practical use immediately where the investigators have to identify the age. Put into practical use, this new discovery will make the task of the crime scene investigators a little simpler.