Resolving Pliocene and Pleistocene Hominin Ontogeny With Synchrotron Virtual Histology

Harvard University, Cambridge MA

Investigators

Abstract

Exploring the evolution of human growth and development is of particular significance for understanding unique attributes of modern humans, such as long childhoods and extended post-reproductive periods. The integration of cutting-edge X-ray imaging, developmental biology, and analyses of the fossil record will reveal the intimate record of birth and subsequent growth recorded in ancestral human remains. More broadly, this project will significantly improve research and education infrastructure through the creation of an open-access virtual hominin database. This will directly benefit students and scholars who are unable to access original specimens and costly equipment, as well as African repositories with limited infrastructure for hosting and disseminating large virtual datasets. The project also will also strengthen and establish novel multidisciplinary international collaborations, protect invaluable fossil material by potentially reducing the demand for access to original specimens, and provides research and training opportunities for students and a postdoctoral fellow in the emerging field of virtual histology. Due to their highly mineralized nature, teeth are the most common elements in human fossil assemblages. Tooth crowns and roots preserve precise records of daily growth, formation time, and age at death in young individuals, remaining unchanged for millions of years. Importantly, the timing of tooth formation is the most accurate proxy for reconstructing growth and development in fossil species. This project will assess the evolution of human development through the study of early hominin dentitions. Cutting-edge synchrotron imaging will be employed to reveal microscopic tooth structure non-destructively and in three-dimensions (3D). In contrast to most preceding studies, which necessarily employed living ape and/or human developmental variables, this project will yield the most comprehensive and independent assessment of development in hominins predating Neanderthals.