Methods
Developing an Integrated Coextraction Protocol: a central aim of this project is to develop a coextraction protocol that enables the simultaneous recovery of materials for microremain analysis, palaeoproteomics, and organic residue analysis from a single dental calculus sample. Traditionally, these methods are performed separately, requiring multiple sub-samples and often leading to destructive consumption of limited material. By integrating extraction steps and optimizing buffer compatibility, this project seeks to maximize data yield while minimizing sample destruction. This holistic approach allows for the combined analysis of plant microremains, proteins, and lipids from the same matrix, offering a multi-dimensional view of diet, health, and environment from a single biomaterial source.
Microremain analysis of dental calculus: an approach that examines particles, primarily of plant such as pollen, spores, phytoliths and starch, and fungal origin through transmitted light and electron microscopy. These microremains can examined in-situ but are usually examined ex-situ and can provide a perspective into plant consumption as well as airborne pollutants.
Palaeoproteomics of dental calculus: this methodology uses liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyse ancient proteins preserved in dental calculus, which remains stable over time due to its mineralized structure. Proteins are extracted, digested into peptides, and identified, enabling the detection of dietary sources such as milk, cereals, and meat. Microbial proteins reveal the composition of the oral microbiome, while human immune proteins indicate oral and systemic health.
Organic residue analysis of dental calculus: this is a method that uses a variety of chromatographic methods to understand organic residues. These include Pyrolysis–gas chromatography–mass spectrometry (Py-GC-MS), a method in which the sample is thermally decomposed to break it into smaller molecules that are separated by gas chromatography and detected using mass spectrometry. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) enables the high-sensitivity separation and structural elucidation of intact polar lipids and lipid-derived metabolites preserved in dental calculus. Both of these appraoches allows researchers to detect and identify organic compounds trapped in ancient dental calculus, offering insights into past human diets, health, environmental exposure, and material culture.
δ13C and δ15N isotopic analyses of collagen: Stable carbon and nitrogen isotope ratios (δ¹³C, δ¹⁵N) from bone and dentine collagen provide insight into diet, subsistence strategies, and the broad environmental zones exploited, following the ‘you are what you eat’ principle. Elevated δ¹³C and δ¹⁵N values typically indicate marine resource consumption relative to terrestrial baselines. Bulk bone collagen in adults reflects long-term dietary averages, while incremental dentine sampling captures short-term dietary signals from early life. Combined, these approaches allow reconstruction of terrestrial vs aquatic and plant vs animal protein intake