By examining the microbial flora of the human navel, scientists have found about 1600 strains of bacteria, more than 600 of which appear to be previously unknown, reports New Scientist.
The first round of research into the DNA of the human navel bacterial flora (Belly Button Biodiversity Project) involved 95 samples. This was enough to find 1400 strains. In 662 cases, these microorganisms could not even be classified into a specific family. According to Jiri Hulcr of North Carolina State University in Raleigh, this suggests that they are new to science.
While the navel project was intended only as an exercise for scientists, it is making a major contribution to improving understanding of the diversity of microorganisms. Volunteers (including Peter Aldhous from New Scientist) took swabs from their navels, and scientists read the sequences of the 16S ribosomal RNA, widely used in studies of bacterial evolutionary relationships. It turned out, among other things, that science communicator Carl Zimmer has Georgenia bacteria in his navel, previously found in Asian soils.
As Hulcr points out, this example shows our ignorance of bacterial biodiversity. We still know little about the species inhabiting different places and we are surprised by what we discover. The system of distinguishing species used is also imprecise – if mammals were to be classified in a similar way, dogs and cats would be one species.
In any case, about 80 percent of the bacterial population of our navels belongs to the 40 most common species of bacteria (PAP).