Deuterostome extracellular matrix structures (ossicles, tubes & gill bars): Evolution, composition and development.

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My program seeks to understand the homology of extracellular matrix structures (EMS) and how they change on evolutionary and developmental time scales. EMS include skeletons, tubes, shells and gill bars. They are widely investigated by paleontologists, developmental biologists, physical chemists, material scientists, medical researchers, and ocean acidification scientists. There are so many materials used and morphologies produced, that common threads connecting basic structures in different taxa are of considerable interest. I study EMS (skeletons, tubes and gill bars) in the deuterostomes. Deuterostomes include three phyla; the Hemichordata are a small group of marine invertebrates that are sister group to Echinodermata (that together form the Ambulacraria'), which in turn is sister to the Chordata. Hemichordates are comprised of two major classes, the solitary acorn worms, and the colonial, tubicolous pterobranchs (including graptolites). Early in my career I hypothesized that chordate gills, including the acellular secreted collagen, are a deuterostome plesiomorphic (ancestral) trait, present in acorn worms, but lost in echinoderms. In the past 5-years I have found support for this hypothesis using comparative and functional morphology, molecular development, comparative genomics including the finding of synteny of pharynx and gill developmental genes, and the discovery of Cambrian fossil acorn worms with gills. Today this hypothesis is widely accepted. Here I propose to adopt the same multidisciplinary approach to test three hypotheses (the first two are novel and attributable to the past 5-years of my NSERC program) on the origin and evolution of deuterostome EMS. My discovery of echinoderm-like skeletal ossicles in acorn worms has led to Hypothesis #1: Echinoderm ossicles are an ambulacrarian plesiomorphy. Secondly, our discoveries of tubicolous Cambrian acorn worms, has led to Hypothesis #2: Pterobranch tubes are a hemichordate plesiomorphy. Finally, we will test Hypothesis #3: Extinct echinoderms (stylophorans) had gills used in filter feeding and lost in modern taxa.*** *Over 5-years my program will support 1 MSc, 5 PhD, 1 post-doc and at minimum 30 undergraduate HQPs. All will gain experience in experimental design, data analysis, technical writing, public speaking and attend weekly lab meetings to discuss papers, student progress, current and emerging methods, tools and theory. My program is a talent pipeline, designed with HQP training at its core. HQPs master cutting edge techniques, in the context of projects that integrate the gene, cell, organism, and population levels of biological organization in two temporal dimensions developmental and geological. The result is HQPs that are collaborative, adaptable, solution oriented and who integrate into academia, industry, medicine, and policy.***