http://www.newscientist.com/article/...ore-germs.html
Ladies, your hands are a zoo. Sampling the bacterial DNA on human skin has revealed that while women's hands get washed more often than men's, they teem with a more diverse selection of germs.
What's more, the average person's hands probably carry at least 3000 different bacteria belonging to more than 100 species. This startling cornucopia may make it possible to tell which objects have been touched by someone, just by looking at the bacteria left behind.
Noah Fierer and colleagues at the University of Colorado at Boulder in the US swabbed the palms of 51 undergraduates coming out of an exam. They then used the PCR technique to amplify the bacterial DNA present, and sequenced the genetic material using a high-throughput method called pyrosequencing.
Previous surveys of skin bacteria involve growing the result of such swabs in culture, but many species were missed as not all the bacteria sampled grew. The new method caught 332,000 genetically distinct bacteria belonging to 4742 different species - a hundredfold increase on previous studies. Each student carried on average 3200 bacteria from 150 species on their hands.