Biomolecular Preservation in Dental Calculus from the Teotihuacan Ritual Landscape

Abstract

The advent of high-throughput sequencing techniques has yielded a wealth of genomic information about the human oral microbiome. This research has expanded with the direct sequencing of DNA from dental calculus (calcified dental plaque) from archaeological material. Archaeological dental calculus is a biomineral that contains remnants of the oral (subgingival) microbiome. While preserved DNA in dental calculus has been characterized from a number of archaeological contexts, similar research in Mesoamerica is needed. This study aims to provide empirical data about biomolecular preservation in Mesoamerican dental calculus by performing DNA sequencing on dental calculus recovered from the Plaza of the Columns Complex and the Moon Pyramid, two archaeological contexts at Teotihuacan. DNA was extracted using a modified Dabney et al. (2013) protocol. The extracts were built into high-throughput (Illumina) shotgun sequencing libraries. Quality filtered sequences were analyzed to evaluate overall DNA preservation (microbial and host), and characterize microbial community profiles. While the samples selected from the Moon Pyramid (n=3) showed strong evidence of post-depositional environmental contamination, a well-preserved microbial community was identified from the Plaza of the Columns sample (n=1). Therefore, this thesis suggests the recovery of biomolecules from a Mesoamerican context varies within a site and that dental calculus is susceptible to taphonomic processes.