CSI – Microbiology

Imagine the day your own bacteria turns you in to the law!

Ah... you're talking about a new forensic tool which uses the bacteria on your skin to identify you!

Here's how it works.

A person's skin has over a thousand types of bacteria; and they differ significantly from person to person, depending on where on the skin you look. For example, only 13% of bacterial types are common to the palms of different people.

So whatever you touch ends up leaving a trail of microbial fingerprints.

This microbial fingerprint can be more reliable than an actual fingerprint since its not surface dependent – meaning, you can recover it from fabrics, for example.

In a study, researchers compared bacterial communities from the keyboards of three people with bacteria from their fingertips. They swabbed the keys and fingertips then isolated the DNA of the bacteria present.

They were able to precisely identify something called 16S RNA genes. These genes are unique to each bacterial type. Once bacteria from the keyboards and fingertips were compared, the correct matches were made.

In another experiment, researchers correctly identified the person who touched a computer mouse from a bank of 270 people.

Another advantage to this method is that experiments show, even when objects were left for up to two weeks after being touched, the bacterial communities could still be matched to the correct person.

That's because bacteria on the skin are highly stable to environmental conditions such as drying, temperature variations and UV exposure. In fact the bacterial communities on our hands are so stable they return to normal levels and composition within hours of hand-washing.

While not quite ready for prime time, this certainly could become a promising new tool for forensic scientists. I can see it now — CSI –Microbiology!