14 DAY TRIAL // A new DNA test makes it possible to estimate the age of a criminal by the blood he/she left behind, thus narrowing down the range of possible suspects.
The test was developed by Manfred Kayser from the Erasmus University Medical Center in Rotterdam, the Netherlands, and colleagues, and they say that their method needs between 5 and 50 nanograms of DNA in order to predict someone's age within 20 years.
This means that a small drop of blood is more than enough, still Peter Gill, a former principal research scientist at the Forensic Science Service in the UK, says that the test is quite limited for now.
He says that “although this test is a useful thing to have in the armory, it would be a lot more practical if the age Brackets could be narrowed down to about five years.”
Before future technology makes this test even more precise, you should know how the team of scientists managed to get to this result.
They took blood samples from 195 individuals, aged from a few weeks to 80 years old, and extracted DNA, NewScientist reports.
Afterwards, they amplified the DNA with a polymerase chain reaction that generated billions of copies of DNA fragments, called sjTRECs, or 'signal joint T-cell receptor rearrangement excision circles'.
These fragments are actually the by-products of the receptors of infection-fighting T-cells, as they rearrange themselves to become more diverse and stronger at fighting foreign agents in the blood by deleting pieces of their DNA.
The interesting fact is that as we age, our level of sjTRECs decreases, so after evaluating the sjTREC level in every sample and comparing it with the age of the donor, the team concluded that the test could accurately predict to what 20-year age range, from birth to 80 years old, the blood sample belonged to.
Kayser says that this method is actually more accurate than the old ones, because the analysis of mitochondrial DNA deletions is unable to detect ages below 20 years old, and it also needs a more intact DNA sample.
Another interesting thing about this new technique is that it actually works on blood sample up to 18 months old, and should it prove to be as accurate for older samples, the researchers believe that it could be very useful in solving past crimes, by an analysis of collected blood samples.