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

我的项目旨在了解细胞外基质结构（EMS）的同源性以及它们在进化和发育时间尺度上的变化。EMS包括骨架、管、壳和鳃杆。古生物学家、发育生物学家、物理化学家、材料科学家、医学研究人员和海洋酸化科学家对它们进行了广泛的研究。使用了如此多的材料，产生了如此多的形态，以致于连接不同分类群的基本结构的共同线索引起了相当大的兴趣。我研究后口动物的骨骼、管和鳃杆。后口动物包括三个门；半足纲是一种海洋无脊椎动物，是棘皮纲的姐妹纲（它们共同构成了棘皮纲），而棘皮纲又是脊索纲的姐妹纲。半足虫由两大类组成，单独的橡子虫和群体的管状翼枝虫（包括笔石虫）。在我职业生涯的早期，我假设脊索动物的鳃，包括脱细胞分泌的胶原蛋白，是一种后口动物的多形（祖先）特征，存在于橡子蠕虫中，但在棘皮动物中却没有。在过去的5年里，我通过比较和功能形态学、分子发育、比较基因组学（包括发现咽和鳃发育基因的合流）以及发现寒武纪有鳃的橡子蠕虫化石，为这一假设找到了支持。今天，这一假设被广泛接受。在这里，我建议采用相同的多学科方法来测试关于后口动物EMS的起源和演变的三个假设（前两个是新的，可归因于我过去5年的NSERC项目）。我在橡子虫身上发现了类似棘皮动物的骨骼小骨，这导致了假设1：棘皮动物的小骨是一种无尾蛇的蛇形。其次，我们发现的管状寒武纪橡子蠕虫，导致了假设2：翼枝管是一种半足状的多形体。最后，我们将验证假设#3：灭绝的棘皮动物（茎突动物）有用于滤食的鳃，在现代分类群中消失了。

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.