March 17, 2010
Late last year, the television show Mythbusters showed that our computer keyboards are crawling with microorganisms. Now scientists from the University of Colorado have shown that those bacteria can be used to identify a computer’s user.
Germophobes don’t want to know this, but our bodies are covered with microorganisms. Some spots have more than others—the index finger, palm, back of the knee, sole of the foot and the arm pit—and washing doesn’t get rid of all the bacteria. Earlier this year, scientists discovered that we all have our own bacterial “signature”: the diversity of those bacteria is different on each person.
Those microbes are easily dislodged, which is how they end up on the things we touch, from door handles to computers. The University of Colorado researchers, who published their study this week in PNAS, went looking for our microbial “trail.” Like the Mythbusters, they took samples of the bacteria on computer keyboards, but they went further, sequencing the bacterial DNA and comparing the composition of the bacterial communities on keyboards to those on the hands of humans that used them. The communities were very similar.
The researchers then devised a test to see if they could use this information to identify a computer’s user. They sampled bacteria from nine computer mice and compared the bacterial communities to those on the hands of the nine computer users and 270 people who had never touched the mice. In each case, the composition of microorganisms on the mice was more like the users than like any of the other people.
This technique isn’t likely to end up in forensic labs any time soon—more research is needed to test and refine the method—but the researchers say that certainly a possibility.
In the meantime, you might want to figure out how to clean your keyboard and mouse.
Sign up for our free email newsletter and receive the best stories from Smithsonian.com each week.