Friday, September 21, 2012

Microcosmos -- part 2

Back in June, the journal Science devoted a special section tp the human gut microbiota, the microorganisms that inhabit our innards, whose cell count outnumbers our own. Recent research has revealed how important these inhabitants are for "our evolution, development, metabolism, immune defense, and susceptibility to a multiplicity of infections and noncommunicable diseases."

Also in June, a consortium of 200 investigators described in detail the microscopic community that resides on our elbows, and more than a dozen other parts of the body. They are part of the massive Human Microbiome Project. By the time the project is completed next year, they will have spent $170 million cataloging the microorganism that live on 18 body sites, and their genes.

To date, the Human Microbiome Project has generated 3.5 terabases of data, more than 1000 times the amount produced by the original Human Genome Project.

The bugs are everywhere -- on our elbows, in our noses, behind our ears, on our genitals -- thousands of species of bacteria, each community adapted to local conditions. My body consists of tens of trillions of cells. It is host to even more tens of trillions of living creatures that are not me, but with whom I live in an inseparable symbiosis.

Cataloging the invisible creatures that inhabit the human body -- its surface and innermost caverns -- is roughly equivalent to cataloging the visible plants and animals that inhabit the planet Earth. Apparently we arrive pristine. But no sooner do we poke our noses into the world than bacteria, fungi and viruses start colonizing our nooks and crannies, like the colonization of a new island arisen from the sea. Wave after wave of pioneers enter our bodies by every access, take up residence in eyelash and groin. By and large, they are mostly welcome, even useful. By and large.

Still, knowing they are there can be unsettling, prompting a gargle with Listerine and a long hot shower. $170 million to to tell us what some of us, perhaps, would rather not know. Just writing about them makes me itch.