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

Abstract

24The trillions of microorganisms that live in association with the human body 25 (microbiota) are critical for human health and disease, but there is a limited 26 understanding of how cultural and environmental factors shaped our microbiota 27 diversity through time. However, biomolecular remnants of the human oral 28 microbiota -recovered from the calcified dental plaque (calculus) of our long-dead 29ancestors -are providing a new means of exploring this key relationship of our 30 evolutionary history. Here, we correlate extensive experimental, archaeological, and 31 biological metadata with 128 ancient dental calculus specimens from Medieval and 32Post-Medieval London, UK (1066 -1853 CE). We identify a significant association 33 between microbiota and oral geography (i.e. tooth type and tooth surface), which has 34 confounded ancient microbiota studies to date. By controlling for oral geography, 35 however, we identify the first associations between ancient microbiota and cultural 36 and environmental signatures. We find significant links between ancient British 37 microbiota structure and health, including skeletal markers of stress that may reflect 38 low socioeconomic status. Furthermore, this study provides baseline data to explore 39 factors that drive microbiota differentiation within and between ancient populations 40 and highlights the potential of ancient microbiota to infer detailed health and socio-41 cultural information about the past.

The evolutionary history of the human oral microbiota and its implications for modern health

“…For example, a survey of British dental calculus up until 1895 identified a significant shift in oral microbiota after the start of the Industrial Revolution. 46 Similarly, a recent study by Skelly et al 105 also identified significant changes in industrial era oral microbiota in the UK, Germany, Switzerland, and Australia, suggesting that changes during this time period were global. Microbial species associated with industrialization differ in individual locations, suggesting that the process of industrialization may have had unique effects in different places.…”

“…The ability to reconstruct ancient oral microbiota preserved in calcified dental plaque (calculus) has emerged as the only way to reproducibly survey ancient human microbiota, 63,64 igniting this new field of research. Using this approach, ancient oral microbiota have been successfully reconstructed from ancient and historic chimpanzees and gorillas, 65,66 Neandertals, 66 and a wide range of ancient anatomically modern humans 46,66‐71 . These studies allow us to survey oral microbiota evolutionary histories in new ways, providing information on the past behaviors of ancient hominids (eg, Neandertals and humans), 66 oral microbiota associations with past diets, 67,68 and relationships between oral microbiota and the origin of disease 46,67,68,71 …”

“…45 While this may provide a way to examine and trace noncommunicable diseases throughout human evolution, it also highlights the need to accurately document and describe oral and systemic health status in past populations, as diseases within a population may obscure evolutionary signals more broadly. 46…”

“…Using this approach, ancient oral microbiota have been successfully reconstructed from ancient and historic chimpanzees and gorillas, 65,66 Neandertals, 66 and a wide range of ancient anatomically modern humans. 46,[66][67][68][69][70][71] These studies allow us to survey oral microbiota evolutionary histories in new ways, providing information on the past behaviors of ancient hominids (eg, Neandertals and humans), 66 oral microbiota associations with past diets, 67,68 and relationships between oral microbiota and the origin of disease. 46,67,68,71 As this is an emerging field, researchers are rapidly working toward methodological advancements, 69,70,72,73 as many of the meth-…”

“…Further, oral microbiota, or at least certain species within the microbiota, may be linked to systemic diseases, such as Parkinson's disease, 41 type II diabetes, 42 inflammatory bowel disease, 43 obesity, 44 or gastrointestinal cancers 45 . While this may provide a way to examine and trace noncommunicable diseases throughout human evolution, it also highlights the need to accurately document and describe oral and systemic health status in past populations, as diseases within a population may obscure evolutionary signals more broadly 46 …”