NPR reports: Scientists Wednesday unveiled the first catalog of the bacteria, viruses and other microorganisms that populate every nook and cranny of the human body.

Researchers hope the advance marks an important step towards understanding how microbes help make humans human.

The human body contains about 100 trillion cells, but only maybe one in 10 of those cells is actually — human. The rest are from bacteria, viruses and other microorganisms.

“The human we see in the mirror is made up of more microbes than human,” said Lita Proctor of the National Institutes of Health, who’s leading the Human Microbiome Project.

“The definition of a human microbiome is all the microbial microbes that live in and on our bodies but also all the genes — all the metabolic capabilities they bring to supporting human health,” she said.

These microbes aren’t just along for the ride. They’re there for a reason. We have a symbiotic relationship with them — we give them a place to live, and they help keep us alive. [Continue reading…]