Hanken 9801586 This study will examine the development of the skull in several species of amphibians (frogs). Its main goals are to better understand the molecular and genetic processes that underlie the embryonic development of bone in the heads of vertebrate animals, and how these processes are modified during evolution to achieve diversity of skull size and shape among species. It also will provide greater understanding of the developmental bases for direct development, a widespread but poorly studied life-history mode found in many species of living amphibians, and how direct development evolved from the ancestral, metamorphic life history. Individual analyses will employ several different laboratory procedures. These include labelling embryonic cells with vital dyes and embryonic tissue recombinations (to identify which cells contribute to the adult skull); histology and immunocytochemistry (to study detailed aspects of cranial anatomy); and recombinant DNA technologies, in situ hybridization, and implantation of protein-soaked beads (to identify genes that are involved in bone formation and determine the likely functions of each). By supporting this research, this award also will enhance the education and training of a postgraduate student and better prepare the PI for a career in higher education and biological research.
