Cameron 9604454 In this project, Dr. Cameron examines the development of indirect developing sea urchin larvae, a life stage that arises from the embryo after the onset of feeding and bears little morphological resemblance to the adult into which it will eventually metamorphose. He focuses particularly though not exclusively on those larval developmental processes that lead to the formation of adult primordial structures. He will employ modern techniques of confocal microscopy, blastomere injection, lineage tracing, in situ hybridization and genetic chimeras to illustrate the developmental mechanism that lead to the formation of larval structures. The studies that he proposes fall into the following categories: 1) The mapping of set aside cell populations through the use of vital dyes, DNA stains and bromodeoxyuridine incorporation. 2) Experiments to alter larval division patterns and to test the cell number regulation in structures stemming from set aside cells. 3) The contribution of isolated animal-half embryos, vegetal-half embryos and the skeletogenic cells to adult structures and the larval primordia from which they arise using genetic chimeras detected by genomic microsatellite markers. 4) The examination of expression in larvae of genes likely to be involved in the formation of adult structures. 5) Observations on the adult rudiment to determine the earliest incidence of pentameral symmetry and the manner in which it is established.
