Microscopic menagerie
New view of microbes forces rethinking of what it means to be an organism
MADE OF MICROBES The microbes dwelling in and on multicellular organisms, such as insects and humans, should be viewed as evolutionarily inseparable from their hosts, some biologists argue.
Nicolle Rager Fuller
What is a wasp?” might seem like an overly simple question for a Ph.D. biologist to be asking. “What is a human?” Even more so.
But these are strange times in the life sciences. Seth Bordenstein of Vanderbilt University in Nashville now embraces the notion that each wasp he studies, each squirrel darting around campus — not to mention himself, every reader of science magazines and every other representative of see-it-without-a-microscope life on Earth — is really a blend of one big organism and a lot of little ones.
In recent years, research has shown that what people commonly think of as “their” bodies contain roughly 10 microbial cells for each genetically human one. The microbial mass in and on a person may amount to just a few pounds, but in terms of genetic diversity these fellow travelers overwhelm their hosts, with 400 genes for every human one. And a decent share of the metabolites sluicing through human veins originates
