As the biology wonks love to point out, you aren't an individual - you're an ecosystem. Most of the cells in your body aren't human, but microbes. And along with mites, every bit of your skin and hair is colonized as well. In fact, it seems you spread your colonies wherever you go, which has some profound implications:
When you move from one house to another, you take all your bacteria with you. In fact, your family's microbiome (or your eco-system of inner and outer bacteria) lays claim to hotel rooms with hours. Our bacterial signatures are so persistent and so unique, a new study published Thursday in Science reports, that they could even be used in forensic investigations — and eventually become more useful to police than an old-fashioned fingerprint.
Fingerprints, after all, are fairly limited; they indicate presence or absence, and even that indicator can be eliminated by careful cleaning of a scene. But you're not going to eliminate all traces of your microbial presence, and so the little bostiches can rat you out regardless of how thorough you think you've been.
We can see who they are, where they're from, the diet they're eating, when they left, who they may have been interacting with.
"If someone is, shall we say, recently and inappropriately deceased," Gilbert said, "we can look at their bacterial colonies and try to identify who the last person to come into contact with them was, and when." Based on some promising animal studies, he said, it could be possible. "An actual fingerprint is rarely left on a body," Gilbert said, "but a microbial fingerprint certainly is."
Charles Schulz had it right with his "Pigpen" character, in which clouds of stuff are shed constantly by the kid as he moves around. We do much the same thing, though not as visible dirt - and with current analytical techniques, considerably more information regarding our movements can be reliably tracked.
It may not be ready for prime-time quite yet, but it's a safe bet that this will become as standard a tool as DNA analysis.