Skeletal proportions are primary to locomotor pattern, habitat, and feeding strategy in primates. A more complete understanding of their evolution requires better knowledge of the mechanisms that govern their development, and by extension, better comprehension of their underlying cellular growth. To this end, the researchers plan to help elucidate the molecular signaling pathways affecting structures known as growth plates and their behavior during ontogeny. The mechanisms that regulate cartilage growth and maturation during embryogenesis (and thus guide formation of the skeletal system) have recently been greatly clarified. However, the role of these same mechanisms in normal postnatal growth is still largely unknown. Some bones grow by direct addition of material while others have specialized areas for longitudinal growth called growth plates. The mammalian metacarpal forms only a single growth plate, such that the other end behaves like bones which lack them. Therefore, it provides an excellent model with which to explore how the molecular signals involved in the regulation of cartilage growth and bone formation via these two separate mechanisms differ, and especially how the environment potential affects each. Comparison of protein expression (immunohistochemistry) between the proximal and distal ends of metacarpals at multiple postnatal age stages in the mouse can illuminate these signals and provide a better understanding of the molecular mechanisms underlying growth specification in mammals. A more thorough understanding of postnatal behavior of growth plates will directly improve our understanding of both human and primate skeletal evolution (as well as similar processes in the base of the skull), and how changes in bone length (and shape) are genetically expressed. Thus, this study will aim to uncover genetic targets available to natural selection for the modification of skeletal proportions.
This research project has a broader impact on science in general because it requires collaboration and interaction between anthropological and biomedical researchers, an increasing necessity as the biological subfields become more diverse and specialized. As always, an improved knowledge of normal biology greatly improves our ability to enhance clinical care; given the variety of growth disorders in humans, the present case is certainly no exception to this general rule. In addition this award will facilitate the education of a promising graduate student.
