[Infowarrior] - Hand germs could join fingerprints, DNA in forensics labs

[Richard Forno]

Hand germs could join fingerprints, DNA in forensics labs
Mar 15 03:13 PM US/Eastern
http://www.google.com/hostednews/afp/article/ALeqM5hNy0acu4hmHKYVDhnGGeA9A56NiA

A woman is fingerprinted. Forensic scientists could soon use hand  
germs to ...

Forensic scientists could soon use hand germs to help identify  
criminals and victims, a study said Monday.
Researchers led by Noah Fierer of the University of Colorado at  
Boulder swabbed individual keys on three personal computer keyboards,  
extracted bacterial DNA from the swabs and compared the results with  
bacteria on the fingertips of the keyboards' users.

They also lifted germs from an unspecified number of other private and  
public computer keyboards that the three individuals did not use to  
see if there was a cross-over between the bacteria on an individual's  
hands and bacteria on keyboards that had never been touched by that  
individual.

The bacteria on each person's fingers were "personal" and gave a much  
closer match to the germs on the keyboard they used than to bacteria  
found on keyboards they had never touched, the researchers said.

The researchers also swabbed nine personal computer mice that had not  
been touched for at least 12 hours and took bacteria samples from the  
palms of their owners.

The bacteria on each mouse were "significantly more similar" to those  
found on the owner's hand than to bacteria taken from 270 other hands,  
which were on record from previous studies.

"Each one of us leaves a unique trail of bugs behind as we travel  
through our daily lives," said Fierer, a professor at the University  
of Colorado's ecology and evolutionary biology department, adding that  
hand bugs could "become a valuable new item in the toolbox of forensic  
scientists."

Hand germs are abundant, can be lifted from small areas and are  
remarkably hardy. The researchers found that colonies of hand bacteria  
remain essentially unchanged after two weeks at room temperature, and  
recovered within hours of handwashing.

Fingerprints, however, can be smudged or impossible to obtain, such as  
on fabric.

And unless there is blood, tissue, semen or saliva on an object, it is  
often difficult to obtain enough human DNA for forensic  
identification, said the study published in the Proceedings of the  
National Academy of Sciences (PNAS).

"Given the abundance of bacterial cells on the skin surface... it may  
be easier to recover bacterial DNA than human DNA from touched  
surfaces although additional studies are needed to confirm that this  
is actually true," the study said.




Copyright AFP 2008,