Biological and cultural drivers of oral microbiota in Medieval and Post-Medieval London, UK

The trillions of microorganisms that live in association with the human body (microbiota) are critical for human health and disease, but there is a limited understanding of how cultural and environmental factors shaped our microbiota diversity through time. However, biomolecular remnants of the human oral microbiota - recovered from the calcified dental plaque (calculus) of our long-dead ancestors - are providing a new means of exploring this key relationship of our evolutionary history. Here, we correlate extensive experimental, archaeological, and biological metadata with 128 ancient dental calculus specimens from Medieval and Post-Medieval London, UK (1066 - 1853 CE). We identify a significant association between microbiota and oral geography (i.e. tooth type and tooth surface), which has confounded ancient microbiota studies to date. By controlling for oral geography, however, we identify the first associations between ancient microbiota and cultural and environmental signatures. We find significant links between ancient British microbiota structure and health, including skeletal markers of stress that may reflect low socioeconomic status. Furthermore, this study provides baseline data to explore factors that drive microbiota differentiation within and between ancient populations and highlights the potential of ancient microbiota to infer detailed health and sociocultural information about the past.