Recent advances in the biological sciences have revealed how genes control the developmental processes that make our teeth. The Tied2Teeth project builds on the discovery that some of these genes also influence the developmental processes that underlie other parts of our bodies, such as hair texture, mammary glands, and body size. We will be investigating the details of how non-dental traits are interconnected with dental variation, how this varies across humans, and how this has evolved through time.
Teeth dominate the fossil and bioarchaeological records because they consist mostly of inorganic material. Consequently, dental anthropology has long been essential in our investigation of the human past. Variation in the anatomy of teeth is instrumental for differentiating species, identifying biological affinities between populations, making inferences about dietary adaptations, and timing key developmental life stages. However, recent advances in genetics, genomics, and developmental biology undermine many assumptions built into anthropologists’ study of the dentition by revealing extensive pleiotropy—when one gene influences more than one anatomical structure simultaneously.
However, this is not a setback but rather an advantage. In this project, we will use the pleiotropies that involve teeth to open windows to the evolution of human anatomies far beyond the dentition. We employ three methodological approaches that utilize pleiotropy to probe different aspects of human paleobiology. The first approach will use quantitative genetic analyses to calibrate the extent to which cranial evolution is genetically correlated with dental evolution.
In the second approach, we employ large historical morphological datasets combined with the modern insight from genome-wide-association-studies (GWAS) to explore how the evolution of soft-tissue anatomy may have driven changes in the dentition.
Finally, we turn to the fossil record. Using traits that were defined using a pleiotropic approach, we test the hypothesis that environmental selection influenced dental variation during two key time periods within the evolution of genus Homo. This project modernizes the study of the human past by incorporating the phenomenon of dental pleiotropy. By combining these three different approaches and a range of time scales, we turn the conundrum of pleiotropy into a powerful tool for studying human evolution.