Thetrace of microbesthat we leave behind could function practically as a fingerprint capable ofreveal our identity, according to a study carried out by American scientists. The technique, released in the magazinePNAS, opens the door to the development of anew forensic identification technique.
“Each of us left aunique trace of bacteriain our daily lives, “said the study’s lead author, Noah Fierer. According to the biologist, although the technique is still in its early stages,” it may eventually become a valuable item in the toolbox of forensic scientists. ” new technique, based ongenetic sequencing, has a70-90 percent accuracy, a percentage that is likely to increase when the method is perfected.
Although scientists were already aware of the great diversity of microbes present on human hands, “the main novelty was to show that these differences could be used to identify objects touched by people, thanks to the microbes they left behind,” says Rob Knight , co-author of the work.
With your hands (and microbes) in the dough
Fierer and his team collected bacterial DNA samples from the keys of three personal computers and matched them with bacteria on their owners’ hands, then compared them with samples taken from other keyboards that had never been used by those subjects. The similarity was much greater between the bacteria of individuals and those of their own computers. The test also worked 12 hours after the computers were last used. On the other hand, when the scientists took skin samples from two individuals and frozen one of them at -20ºC and left the other at room temperature for two weeks, they found that the bacterial colonies did not undergo changes in any of the cases.
This technique can also be valuable for forensic medicine when it is difficult to obtain human DNA because there are no traces of blood, tissue, semen or saliva on an object, according to Fierer. “Due to the abundance of bacterial cells on the surface of the skin it might be easier to collect bacterial DNA than human DNA from touched surfaces,” he noted.
