From now on you will no longer be able to lie about your age. Scientists at the University of California (UCLA), in the United States, have just developeda test that allows you to find out how old you are from a simple saliva sample. “By analyzing only saliva we can know the age of a person without knowing anything else about it,” explains Eric Vilain, professor of human genetics at UCLA and co-author of the study published in the journal Public Library of Science (PLoS) ONE.
To develop their technique they paid attention to a process calledmethylation, that is, a chemical modification of one of the four basic pieces that make up DNA, cytosine. According to Vilain, methylation patterns change as we age. Studying 34 pairs of identical male twins between the ages of 21 and 55, they identified 88 different sites in DNA that correlate methylation with age. They then repeated their findings in 60 men and women ages 18 to 70. Finally they verified that by analyzing only two or three genes of those they had identified, they showed that they couldcorrectly predict the age of a person with a maximum margin of error of five years.
Vilain and his colleagues say the test could bevery useful for forensics at the scene of a crime. From saliva left on a toothbrush or a cup of coffee, the approximate age of a suspect could be ascertained.
On the other hand, in a minority of the population, methylation is not related to a person’s chronological age. Using this data, scientists might one day be able tocalculate the biological age of a person, different from their chronological age. They could also assess the risk of aging-related diseases in a routine medical test based on the biological age of the patient, which is “true DNA age” according to VIlain, and not what appears on their identity card.
