Lifestyle can shape the composition of beneficial bacteria and other microorganisms within the mouth, according to a new study led by Penn State biologists. The international team revealed how the oral microbiome differs over a range of subsistence strategies—from nomadic hunter gatherers to farmers to industrialized groups—and found that lifestyle, as well as specific lifestyle factors like smoking, can shape the microbiome. A paper describing the results appears Nov. 4 in the journal Microbiome.