Collaborative Research: Advancing human epigenetic age estimation methods for archaeological and forensic research

Age at death estimates are critical for the study of demography and health in past populations and for correct identifications in forensic cases. However, the accuracy and reliability of age estimation methods based on the human skeleton have limitations resulting from biases in the age, ancestry and sex composition of the collections originally used to develop them. This project advances research on an alternative skeletal age-estimation method based on the analysis of chemical changes that occur in human DNA as we age and can be preserved in the skeleton. To date, applications of such epigenetic methods have been primarily limited to blood and cheek DNA sources. This study advances epigenetic methods that use DNA extractions obtained from bone. Workshops to learn the theory and application of this new method are open to students, faculty and other researchers. Engagement and outreach opportunities are offered - introducing participants to epigenetic methods as applied to studies of human variation, and aging and health in the past. A high-quality short film about the anthropology of aging and the epigenetic clock is made freely accessible to other researchers and the public. This study develops a new method for biological age estimation from the human skeleton, using a genome-wide age-associated DNA methylation approach tailored to damaged/degraded DNA. The project aims to: (1) develop and validate a cost-efficient, robust-to-degradation, genome-scale method for methylation typing, (2) develop a high-quality predictive model of age from methylation signals in bone, and (3) characterize the potential impact of lifestyle factors on any discrepancies between chronological and biological (DNA methylation) ages. Parts 1 and 2 of this study are based on an integrative genomic-osteological analysis of 100 individuals with documented age, sex, and postmortem exposure to various taphonomic conditions from the University of Tennessee, Knoxville, Donated Skeletal Collection. The project integrates epigenomic, osteological, and lifestyle data, broadening the applications of this method. The study analyzes the relationship between biological and chronological age in the context of osteological signs of aging and stress, differentiating the biological and developmental roots of osteological traits used to estimate age in past populations and individuals. This project is jointly supported by the NSF Biological Anthropology program and the National Institute of Justice, Office of Investigative and Forensic SciencesThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.