Researchers have characterized the oral microbiomes of the Japanese population across time by analyzing the DNA preserved in dental calculus of human skeletal remains. The researchers compared microbial composition in dental calculus primarily from Edo-period individuals with that of modern dental c alculus, and identified differences associated with time period, region, and the phylogeny of several oral bacterial species. The findings show that dental calculus can provide new avenues for examining human history and the relationships between humans and microorganisms. The work appears in Scientific Reports . ...read more read less