Using the Ancient DNA in Dental Calculus to Understand the Effects of Urbanization across the Black Sea Region (15 min)

Presenters

Sterling Wright, Pennsylvania State University; Marine Chkadua, Georgian National Museum; Sorin Ailincai, Bucharest University; Alexandra Tarlea, Bucharest University; and Laura Weyrich, Pennsylvania State University

Abstract

Urbanization remains one of the most important cultural developments in human history. While many bioarchaeological studies investigate the effects of urbanization on human health, quantifying its consequences or understanding the biological mechanisms that underpin its associated changes continue to be a significant challenge. As current approaches comparing the skeletal markers between urban and rural cohorts are limited, new tools that assess what health transitions are linked to urbanization need to be developed. Studying the DNA in dental calculus of past populations may bridge this gap because ample evidence on present-day populations suggests that urbanization impacts oral microbiomes. Here, we analyze the ancient DNA in the dental calculus of populations in the Black Sea region, specifically Georgia and Romania, to examine if urbanization impacted their oral microbiomes and if these observations could be linked to disease. We collected dental calculus samples from individuals dating to the Bronze/Iron Ages (1,500 B.C.E.–500 B.C.E.), Roman antiquity (200 C.E.–599 C.E.), and the Middle Ages (1,300 C.E.–1599 C.E.). Rich archaeological assemblages and paleopathological work indicate that urbanization intensified throughout these cultural periods. We characterized the oral microbiome of these populations using a shotgun metagenomic sequencing approach with MALTn, and authenticated the DNA using MapDamage2, SourceTracker, and decOM. Microbial diversity was evaluated with D-MANOVA, while differentially abundant species were evaluated with MaAslin2. Lastly, we incorporate the paleopathological analyses in our models to assess whether individuals with oral diseases have distinct oral microbiomes from their nondiseased counterparts. Our study is one of the first to compare the ancient oral microbiomes in the Black Sea region and provides a novel way of integrating ancient DNA data alongside traditional bioarchaeological analyses to answer questions related to urbanization and its impact on the health of past populations.