August 29th 2013 |
A new study details the microbial contents of 60 volunteers’ belly buttons.
The upshot? Belly buttons, it turns out, are a lot like fluffy rain forests.
Welcome to the Jungle
From 60 belly buttons, the team (Rob Dunn) found 2,368 bacterial species, 1,458 of which may be new to science.
Some belly buttons harbored as few as 29 species and some as many as 107, although most had around 67. Ninety-two percent of the bacteria types showed up on fewer than 10 percent of subjects—in fact, most of the time, they appeared in only a single subject.
One science writer, for instance, apparently harbored a bacterium that had previously been found only in soil from Japan—where he has never been.
Another, more fragrant individual, who hadn’t washed in several years, hosted two species of so-called extremophile bacteria that typically thrive in ice caps and thermal vents.
Despite the diversity, themes emerged.
Even though not a single strain showed up in each subject, eight species were present on more than 70 percent of the subjects. And whenever these species appeared, they did so in huge numbers.
“That makes the belly button a lot like rain forests,” Richard Dunn said who conducted the research. In any given forest, he explained, the spectrum of flora might vary, but an ecologist can count on a certain few dominant tree types.
“The idea that some aspects of our bodies are like a rain forest—to me it’s quite beautiful,” he added. “And it makes sense to me as an ecologist. I understand what steps to take next; I can see how that works.”
Method to the Madness?
But predicting which species might like to call the human body home is only the first step. To make the knowledge useful, scientists need to know why these bacteria show up.
“We’re all like the guys before Darwin who went out and brought this stuff on the ship and said, Check out this bird that’s totally weird—this has got to be important!
“They were still so far from understanding the big picture,” Dunn said. “That’s where we are.”
Hoping to answer those broader questions, Dunn’s team is already working on several hundred more navels—soon to be 600. They’ll use those new samples to start testing the correlation of the navel dwellers with everything from subjects’ places of birth to the makeups of their immune systems.
Making connections such as these could help shed light on the ties between our bacterial hosts and their effects on health. Researchers believe that microbes—not just in the belly button but in every nook and cranny of the human body—are involved in everything from immune function to acne to skin softness. The potential boon to medicine is enormous but out of reach until scientists can clarify what the microbes are doing in the first place, and why they’re there.