BAC and YAC Libraries for Exploring Metazoan Origins

完整地描述多细胞动物的进化史需要在整个动物系统发育树中从门中获得关于动物基因组的内容、组织和调控机制的详细信息。对于这类研究来说，特别重要的是早期从其他动物和与动物近亲的单细胞生物中分化出来的物种。这些生物的基因组特征与最近分化的动物共有，那么这些特征就会出现在所有现代动物的祖先身上。本项目的目的是准备和存档来自线虫（Nematostella vectensis，一种海葵，是早期分化的动物门刺胞门的成员）和短单胞单鞭毛菌，一种与多细胞动物密切相关的单细胞生物的细菌人工染色体文库。这些文库将为解决与多细胞动物的起源、进化和发展有关的各种问题提供重要的资源。这些问题包括：发育调节基因的Hox家族是如何进化的？在动物进化过程中，其他各种发育调节基因家族是什么时候出现的？鞭藻与多细胞动物的关系有多密切？从单细胞动物向多细胞动物过渡需要哪些基因？当神经被添加到多细胞动物中时，在基因组水平上发生了什么？在现代动物的共同祖先中存在哪些细胞粘附和细胞间信号分子？刺胞动物的基因是否像这个门中存在的剪接前导加法所暗示的那样被组织成操纵子？除了为动物进化分析提供材料外，这些文库还将促进基因启动子的分离，这对于开发这些生物的功能分析和解剖基因调控网络至关重要。该项目生成的库将免费提供给研究社区。有关这些图书馆及其可用性的信息将通过各种途径提供，包括适当的科学新闻组和网站。

0208335SteeleA complete description of the evolutionary history of multicellular animals will require detailed information on the content, organization, and regulatory mechanisms of the genomes of animals from phyla throughout the animal phylogenetic tree. Of particular importance for such studies are species that diverged early from the rest of the animals and unicellular organisms which are close relatives of animals. Features of the genomes of such organisms which are shared with more recently diverged animals would then be ones which were present in the ancestor of all modern animals. The goal of this project is to prepare and archive bacterial artificial chromosome libraries from Nematostella vectensis (a sea anemome which is a member of the early diverging animal phylum Cnidaria) and from the choanoflagellate Monosiga brevicollis, a unicellular organism closely related to multicellular animals. These libraries will provide important resources for addressing a variety of questions related to the origins, evolution, and development of multicellular animals. Such questions include: How did the Hox family of developmental regulatory genes evolve? When did various other developmental regulatory gene families appear during animal evolution? How closely related are choanoflagellates and multicellular animals, and what genes were necessary to make the transition from unicellularity to multicellularity? What happened at the genome level when nerves were added to multicellular animals? What cell adhesion and intercellular signaling molecules were present in the common ancestor of modern animals? Are cnidarian genes organized into operons, as suggested by the presence of spliced leader addition in this phylum? In addition to providing material for analysis of animal evolution, the libraries will facilitate the isolation of gene promoters, which will be essential for the development of functional assays in these organisms and for dissecting gene regulatory networks. The libraries generated by this project will be freely available to the research community. Information on the libraries and their availability will be provided through various means, including appropriate scientific newsgroups and web sites.