Scientists use their hands a lot, doing all sorts of things like working with complex equipment, or viewing things under a microscope. But, Noah Fierer decided the hands themselves, needed studying. Specifically, the bacteria that live on your hands. Sampling male and female hands showed a surprising difference.
"We found that men and women have very distinct communities. So, essentially we answered the age-old question, 'do girls have cooties?''"
While Fierer jokes about that result, learning about the different bacteria on your hands is important for understanding health. To really tell species of bacteria apart, scientists have to look at their DNA. Only recently did DNA sequencing become fast and cheap enough to do a survey of bacteria communities on a bunch of hands. Fierer sampled the hands of more than 50 students at the University of Colorado at Boulder and found on average, only 17 percent of the bacterial communities on your left hand are shared by your right hand.
And washing doesn't always get rid of the bacteria, at least not for a very long time. They found between two and four hours after hand washing, the community was back to normal levels.
Next, Fierer wants to learn about "who" is on our hands: which species of bacteria, what they are doing there, and whether certain communities of bacteria make one more resistant or more susceptible to acquiring skin diseases.