Forensic scientists have devised a technique for estimating human age from blood collected at a crime scene.
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SYDNEY: Forensic scientists in the Netherlands have developed a reliable technique for estimating human age from just a single drop of blood.
Of the tool's various potential applications, it could be especially useful to law enforcement seeking to determine the identity of missing persons or criminal suspects from blood collected at a crime scene.
"Our test holds great promise for application in forensic age estimation, particularly in cases where only blood is available, such as is usually the case with violent crimes", said molecular biologist Manfred Kayser from Erasmus MC in Rotterdam, a co-author of the study published in Current Biology .
Vastly superior technique
Until now, crime scene investigators have depended on the availability of specific body parts, such as teeth, bones or ligaments, for estimating the age of otherwise unidentifiable persons.
This new technique is vastly superior because it relies solely on the availability of a relatively small blood sample.
It takes advantage of a phenomenon known as thymus involution, which begins shortly after birth. As a person ages and the thymus tissue degrades, the quantity of a particular type of DNA molecule within our immune cells - signal joint T-cell receptor excision circles, or simply sjTRECs - declines at a steady rate.
Accuracy of nine years
In their study, Kayser and his team took blood samples from 195 healthy Dutch individuals, ranging in age from a few weeks to 80 years of age.
After quantifying the amount of sjTRECs in each sample, together with a reference gene to compensate for the total amount of starting DNA material, the researchers ran a regression model comparing sjTREC abundance and age.
They discovered that sjTREC abundance accounted for a highly significant portion of the total age variance, with an accuracy of around nine years. It suggests the tool would be highly accurate in assigning unidentified persons into generational categories, each spanning 20 years.
