The Evolution of Modularity in the Dentition of Old World Monkeys

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Two fundamental questions in biology concern the relationship between genes and anatomy. How does the genotype effect the phenotype? And how has this relationship influenced morphological evolution as seen through the fossil record? In this project, the investigators will test hypotheses about genetic correlations and investigate how these correlations evolved through time. This project focuses on dentition in a model organism that is the most pragmatic from a genetic and paleontological standpoint -- baboons. Through a previous NSF grant, the investigators identified and quantified genetic variances and covariances among more than 200 traits in the dentitions of an outbred population of pedigreed breeding baboons housed at the Southwest National Primate Research Center in Texas. They now will test to see if these correlations are maintained across closely related primate taxa both synchronically (across extant Old World Monkeys, relying on museum skeletal collections) and diachronically (through the last 15 million years of Old World Monkey evolution, using three fossil assemblages recently recovered in Kenya and Ethiopia). If the correlations between dental traits, identified through quantitative genetic analyses, do demonstrate a reliable stability across species, genera, and time, then they will provide the foundation for better phylogenetic reconstructions as well as elucidate the evolution of the molecular genetics of the primate dentition.This project is possible because of the increasingly integrative nature of biological research. The investigators combine the seemingly disparate fields of paleontology and quantitative genetics to better understand the genetic and evolutionary forces that have shaped the dentition. The approach is based on sound and demonstrated quantitative genetic theory that has been successful in other applications. The dentition is an ideal anatomical region on which to test these hypotheses due to the larger genetic component to its variation relative to the rest of the skeleton, the advances in dental developmental genetics over the last decade, and the fact that teeth are the most frequently preserved elements in the fossil record. Baboons provide one of the most useful animal models because of their relatively conserved dental anatomy (compared to the derived dentitions of mice, for example). A fairly well documented and well-studied fossil record exists of their evolution over the last 15 million years in eastern Africa.In addition to the research itself, this project will increase diversity, training, and collaboration within the biological sciences. Funding, in part, is designated for a post-doctoral researcher's support. This person will be a specialist in statistics, who will then be trained in osteology and paleontology, or the contrary, a specialist in the latter disciplines who will be trained in the former. In addition to advancing the principal investigator's scientific career, a woman, a graduate student, and numerous undergraduates will be part of this project, thereby providing numerous educational opportunities. Scientists affiliated with over 12 research institutions are collaborating on this project. This collaboration will increase ties between these scientists and institutions, including public, private, and foreign universities, a biomedical research facility, a national primate research center, and numerous museums. The postdoctoral scientist and students will have significant opportunities to travel domestically and internationally, establishing professional contacts and relationships that will contribute significantly to their academic development. The highly collaborative nature of this project provides the ideal forum through which other integrative research ideas will be generated.