A map of our microbial menagerie

You’re barely human. For every one of your own cells in your body, there are many microbial ones. They not only outnumber you, but they affect your health and your mind. Bits and pieces of this microbial menagerie have been revealed over time, but a massive study – the Human Microbiome Project – has just unveiled the most thorough picture yet of the microscopic majority that colonises us. I wrote about this for The Scientist, so head over there to guzzle the details. The key point, however, is individuality. While some broad groups of microbes that everywhere, the study failed to find any species that are universally present in the same body part across all people. However, those incredibly diverse microbes do very similar things. Curtis Huttenhower, the lead author of this consortium of hundreds, compared the situation to the fact that every city has lawyers, bankers and salesmen, even though different individuals play those roles in different places.