As has been written on Scope before, for every human cell in your body, there are ten bacterial cells living on or in it. Now it appears that you may leave a uniquely identifiable trail of those cells while you work on your computer. According to an article today in Ars Technica's Nobel Intent:
Our skin houses large bacterial ecosystems and, even after washing your hands, the bacterial community is restored within a matter of hours. Scientists have suspected for some time that we might leave "trails" of this skin bacteria on things we touch during the course of a day, and more importantly, that the bacteria might be traceable to individuals. It's not that each person has a unique bacterial species, but that their ecosystems contain different mixes of species, each present at different frequencies.
To test the usability of skin bacteria as an identifier, the researchers took samples of bacterial remnants from mice and keyboards:
The bacterial communities on keyboard samples were compared to those from a range of samples from other public and private keyboards. They used barcode pyrosequencing to sort out the samples, and found each key yielded an average of 1400 bacterial DNA sequences. In each case, there was a significant correlation between the bacteria on the key and on the user's skin. The data showed that the differences in the bacterial communities between users was significantly larger than the difference between the bacteria community from the keyboard and the users' actual skin bacteria composition.
The study was published in the Proceedings of the National Academy of Sciences last month. According to the researchers, much work remains to be done before their techniques will be usable forensic tools.
Previously: Your own unique microbial cachet?