The microbes living on people's tongues tend to cluster with members of their own species, Science reports.
Researchers led by Gary Borisy from the Forsyth Institute used multiplexed fluorescence spectral imaging to explore how the tongue microbiome is organized. As they recount in Cell Reports, he and his colleagues used sequencing data to develop oligonucleotide probes for the major taxa on the tongue and image them. Through this, they found the tongue microbiome is highly structured and forms localized regions where a single taxon dominates.
While samples included free bacteria, they also included bacteria organized into complex biofilms. Certain bacteria, they further note, tended to be in particular parts of those complexes. For instance, Actinomyces was typically near the core of the complex, Rothia tended to be in patches near the exterior, and Streptococcus formed a thin layer on the exterior but also formed patches on the interior of the complex.
"From detailed analysis of the structure, we can make inferences about the principles of community growth and organization," Borisy, who is also at the Harvard School of Dental Medicine, says in a statement. "Bacteria on the tongue are a lot more than just a random pile. They are more like an organ of our bodies."