Population-specific patterns of heritability and integration in the human dentition

Arizona State University, Scottsdale AZ

Investigators

Abstract

Teeth are an extraordinary resource for paleoanthropologists and archaeologists. They preserve well in the fossil and archaeological records, and contain a great deal of information about diet, environment, growth and development, and relatedness among populations or species. However, the underlying biological processes influencing diversity in tooth form have yet to be fully established. This project uses dental cast samples and family genealogies from diverse bioregional samples to better understand the factors that influence the expression of shape characteristics on an individual tooth, among teeth within an individual's dentition, and among human populations. The findings from this project will advance knowledge about how tooth formation is shaped by genes, development, and childhood environment. The investigators will create an archive of high resolution 3D tooth scans and anonymized genealogies that will be hosted online and made freely available to a global network of scholars. This archive will enhance the research and educational infrastructure for not only biologists and anthropologists, but also clinical dentists, orthodontists, and forensic odontologists who conduct primary research in applied fields. Additionally, the work supports undergraduate and graduate student training at Arizona State University, a diverse and inclusive environment with a high representation of Hispanic and Native American students. This research uses measurements and observations on the crests, cusps, and furrows that characterize mammalian tooth crowns. Despite their use by numerous scholars across diverse fields, we still do not fully understand how the process of tooth formation is genetically controlled and how different teeth within the dentition are integrated with respect to developmental processes that include both genetic and non-genetic factors. In this project, 150-250 observations will be collected from each of approximately 3,000 individuals from five samples representing distinct modern human populations. Quantitative genetic analyses will be used to estimate the relative contribution of genes and environment in determining variation in tooth size and shape (heritability). Estimates of genetic correlation (pleiotropy) among dimensions and shape variables will define how an organism forms similar tissues (teeth) at different times (in-utero versus early childhood) under the same developmental program and with input from overlapping genetic factors. These estimates will be compared across the five populations to assess whether a general human pattern is evident, and if not, to determine what factors explain disparities between populations. Results will yield insights into how researchers can use dental data as a genetic proxy measure, with an emphasis on the use of teeth from archaeological or forensic contexts. This 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.