Study Suggests Environment, Not Genetics, Shapes Oral Microbiome

A team from the United Kingdom suggests environmental influences may play a larger role in establishing an individual’s salivary microbiome than genetics. Published in MBio, the study, “The Human Salivary Microbiome Is Shaped by Shared Environment Rather Than Genetics: Evidence From a Large Family of Closely Related Individuals,” offers new insight into how this group of organisms is established, and which factors are chiefly responsible for the microbial mix that plays a central role in oral and systemic health.

The researchers sequenced the bacterial DNA signatures in saliva samples from 157 Ashkenazi Jewish family members living in households in four cities on three continents, plus 27 unrelated Ashkenazi Jewish controls. They found the core salivary microbiome across all samples to be made up of microbes from the genera Streptococcus, Rothia, Neisseria and Prevotella. Using statistical methods to compare factors, such as shared household and genetic relatedness to determine which elements are responsible for the most variation, the authors’ identified household as the factor that determined who shared the most similar salivary microbiomes.

According to the study, spouses, parents and children younger than 10 living in the same household had the most similar salivary microbiomes. “These results support the concept there is a consistent core microbiome conserved across global scales, but that small-scale effects due to a shared living environment significantly affect the composition of the microbial community,” the researchers note.