Some people get a thrill from getting their genome sequenced and poring through the details of their genes. I’m a bit off-kilter, I guess, because I’m more curious about the genomes of the things living in my belly button. And let me tell you: it’s a jungle in there.

I first became curious about my navel in January. I was in Durham, North Carolina, to attend a meeting, and as I walked out of a conference room I noticed a cluster of people in the lobby handing out swabs. They were asking volunteers to stick the swabs in their belly button for the sake of science. Our bodies are covered with microbes, and scientists are discovering weirdly complex patterns to