Reconstructing rapid, post-migratory biological adaptation using ancient dental calculus

As humans migrated across the globe in the past, new diets, environmental exposures, and lifestyle practices likely influenced health in different ways and simultaneously impacted the beneficial microorganisms that live within the human body – the microbiome. Understanding how the human microbiome adapted to new pressures is critical for understanding human health in the past and uncovering the origins of chronic diseases like obesity, cardiovascular disease, and poor oral health. In this project, the research team uses ancient calcified dental plaque to reconstruct the history of microorganisms that were part of Ancestors’ human oral microbiome and estimate how these microorganisms changed over time with shifts in lifestyle and environment. The research advances understanding about how past histories, exposures, and arrivals in new areas around 1,000 years ago may have contributed to human health. The project supports graduate student training and mentoring and international research collaborations. Community-engagement and student exchanges throughout the project ensure that findings from this study are translated into practice in academic journals and local outlets. This research team reconstructs ancient human microbiomes using ancient DNA sequencing from calcified dental calculus. They test how shifts in diet, (i.e., the use of new food sources), changes in environment or landscape (i.e., settlement in high or low altitude), and interactions with new people (i.e., arrival of other populations to the area) influenced the diversity of microorganisms in these Ancestors. More detailed analyses identify the specific genomic adaptations and rearrangements in individual microbes that accompanied these community-based shifts. These microbial adaptations are examined in the context of past human health to understand how these mechanisms may be related to the development of modern chronic diseases.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.