International Research Fellowship Program: Ontogenetic and Evolutionary Shape Variation and Modularity in the Mammalian Skull

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0502186GoswamiThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Anjali Goswami to work with Dr. Marcelo Sanchez-Villagra at the Natural Museum of Paleontology in London, UK.Development is often presented as a major influence on morphological variation, which provides the raw material for evolution. Explicit tests of this hypothesis require quantification of developmental shape to measure its influence on adult variation, but, thus far, quantification of developing morphology has been hindered by difficulties in obtaining measurements from sectioned histological specimens. This study adapts new imaging and digitizing software to construct 3-D models from sectioned material. With these models, Dr. Goswami conducts morphometric analysis of ontogenetic shape in the mammalian skull to test fundamental hypotheses on the influence of development on adult morphology. Previous work by Dr. Goswami has shown that the adult mammalian skull is divided into several independent components, or modules, that can vary independently of each other. Those studies suggested that the observed modules in the adult skull are created and influenced by interactions among developing bones. Measuring the changes in shape and variation during skull development allows for direct testing of the influence of development on adult skull shape. This ontogenetic data is then incorporated into computer simulations to model evolutionary change to determine how developmental differences in skull modules may create the observed differences across mammalian species.This study provides the first comparative morphometric dataset spanning the development of a complex system, the mammalian skull. The new methodologies and analyses developed in this study greatly expand the current scope of embryological and morphometric research. This unique dataset will also be useful for many other studies, spanning developmental genetics, suture formation, evolutionary rates, and phylogenetics, as well as providing extensive comparative data for medical research of developmental disorders.