Evolution of Novel Ontogenies

0234576 RaffThe项目的目标是了解发展演变的机制，以及发展过程如何影响或限制进化的方向。 本研究中使用了两种具有高度不同的早期发育模式的海胆。瘤突杀螟的发育方式为祖先的间接方式，而瘤突杀螟H.红纹直接从胚胎发育到幼成虫。 鸡蛋H。erythrogramma由H. tuberculata精子通过一种新的途径发育，其中通过来自父本基因组的显性因子的作用恢复了许多原始pluteus特征。 Raff博士利用了恢复pluteus组织，口腔外胚层中pluteus样基因表达的恢复，以确定参与发育模式进化的候选调控基因。 关于H.将测试红纹症，并通过功能测定研究幼虫和母体特征进化的基因。 具体目标是：（1）确定调控基因在间接、直接和杂交胚胎中的功能作用。 功能增益的研究将与假定的显性调节基因选择的组织中的间接开发人员的已知角色。 这些将以H表示。将红纹夜蛾胚胎作为注射的mRNA，以确定哪些幼虫特征被转录因子mRNA恢复。 (2)确定影响初级幼虫轴及其进化的基因的功能作用。 候选基因的功能将通过mRNA的错误表达来研究，这些mRNA包括编码信号系统组分、转录因子和这些组分的敲除/敲低构建体的mRNA。 (3)使用跨物种杂交研究细胞谱系转化和新的基因表达模式。 他将使用杂交细胞谱系追踪来确定哪些卵裂球改变命运成为口腔外胚层，以及其他细胞谱系的变化。 符合NSF审查标准：（1）拟议活动的智力价值：该项目将通过确定发育调节基因的功能如何影响发育的进化来推进知识。 该项目将有助于生物学的一个新学科。 该项目利用澳大利亚独特的生物和资源，并包括与澳大利亚科学家的长期合作。(2)拟议活动的更广泛影响：主要的社会影响是帮助建立一个更综合的生物进化观。 这对于在中学和大学生物课上以现实的方式教授进化论很重要。 此外，这项工作本身已被引用在大学教科书，（弗里曼和赫伦，《进化分析》，普伦蒂斯霍尔，2001年; Wilt和Hake，《发育生物学原理》，Norton，2001年，和吉尔伯特，《发育生物学》，Sinauer，2000年），以及大众媒体（华盛顿邮报，2000年10月，国家地理，2000年5月），这有助于创造一个更大的公众了解生物学研究。

0234576RaffThe goal of this project is to understand the mechanisms by which development evolves, and how developmental processes influence or constrain the direction of evolution. Two related species of sea urchins with highly different modes of early development are being used in this study. Heliocidaris tuberculata develops in the ancestral indirect mode via a feeding larva, whereas H. erythrogramma develops directly from embryo to juvenile adult. Eggs of H. erythrogramma fertilized by H. tuberculata sperm develop via a novel pathway in which a number of the primitive pluteus features are restored by the action of dominant factors derived from the paternal genome. Dr. Raff has exploited the restoration of pluteus-like gene expression in a restored pluteus tissue, oral ectoderm, to identify candidate regulatory genes involved in evolution of developmental mode. A hypothesis for evolutionary change in larval form of H. erythrogramma will be tested, and genes underlying evolution of both larval and maternal features will be studied through functional assays. The specific aims are (1) Determine the functional roles of regulatory genes in indirect, direct, and hybrid embryos. Gain of function studies will be done with presumptive dominant regulatory genes selected for known roles in organization of indirect-developers. These will be expressed inH. erythrogramma embryos as injected mRNAs to determine which larval features are restored by transcription factor mRNAs. (2) Determine the functional roles of genes affecting primary larval axes and their evolution. Functions of candidate genes will be studied by misexpression of mRNAs that include those encoding signal system components, transcription factors, and knockout/knockdown constructs for these components. (3) Use cross-species hybrids to investigate cell lineage transformations and novel gene expression patterns. He will use cell lineage tracing in hybrids to define which blastomeres shift fate to become oral ectoderm, as well as other cell lineage changes. Meeting NSF Review Criteria: (1) Intellectual merit of the proposed activity: The project will advance knowledge by determining how the function of developmental regulatory genes influences the evolution ofdevelopment. The project will contribute to a new discipline in biology. The project makes use of unique organisms and resources in Australia, and includes long-term collaborations with Australian scientists. (2) Broader impacts of the proposed activity: The main societal impact is to help create a more integrated view of biological evolution. This is important in teaching evolution in a realistic way in biology classes at secondary and college levels. In addition, the work itself has been cited in college text books, (Freeman and Herron, Evolutionary Analysis, Prentice Hall, 2001; Wilt and Hake, Principles of Developmental Biology, Norton, 2001, and Gilbert, Developmental Biology, Sinauer, 2000), and the popular press (Washington Post, October, 2000, and National Geographic, May 2000), which helps create a greater public understanding of research in biology.