Construction of BAC Libraries of Metazoans Occupying Key Phylogenetic Positions

系统发育关键位置的后生动物 BAC 文库的构建

• 批准号: 0208138
• 负责人: Linda Holland
• 金额: $ 144.73万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Cooperative Agreement
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0208138&HistoricalAwards=false
• 关键词: Construction; BAC; Libraries; Metazoans; Occupying

Large-insert libraries of genomic DNA are a valuable resource for comparative studies indevelopment evolution and genetics for addressing such fundamental questions in biology ashow genomes have evolved and how evolution of genomes has resulted in evolution of bodyplans. The goal of the proposed research is to construct 11 BAC libraries representative of thebreadth of the Metazoa. The focus is on animals that occupy phylogenetic positions key to anunderstanding of animal evolution. Preference is given to organisms with demonstrated potentialas developmental model organisms. Therefore, 2 deuterostomes have been chosen: lamprey,basal in the craniates and pivotal for understanding the pattern of gene and chromosomalduplications during vertebrate evolution, and the cephalochordate amphioxus, the closest livinginvertebrate relative of the vertebrates. On the basis of molecular phylogenetics, the protostomeshave recently been divided into two groups, the Ecdysozoa and the Lophotrochozoa. However,branching patterns of the phyla within each of these groups are poorly resolved. Becauserepresentatives of the Ecdysozoa, Drosophila and Caenorhabditis have been well-studied, wehave not chosen any Ecdysozoan. For the Lophotrochozoa, which have, in general, received littleattention in regard to genes, development and evolution, seven organisms have been chosen.These include 2 annelids, one of which, the polychaete Platynereis dumerilii, is relatively basalwithin the annelids and the other of which, the leech Helobdella robusta, is more highly derived.Platynereis is rapidly becoming a lophotrochozoan model developmental organism, and whilethe leech is quite derived, it has been the object of developmental genetic studies for some years.Two molluscs are included-- one bivalve, (Spisula solidissima) and one gastropod (Ilyanassaobsoleta). The other Lophotrochozoans include 1 nemertean (Cerebratulus lacteus), 1 sipunculid(Temiste langiformis), and 1 acoel flatworm (Neochildea fusca). The phylogenetic position ofthe acoels is controversial. On the basis of morphology, they were considered basal Bilateria.However, most, but not all, molecular phylogenetic analyses place acoels within the protostomes.To address bilaterian origins, we have chosen a ctenophore (Mnemiopsis leidyi). Finally, toaddress the origin of the metazoa, a sponge, Callyspongia diffusa, a representative of the mostbasal Metazoa, was selected. BAC libraries will be constructed and distributed by P. de Jong(Children's Hospital Research Institute, Oakland), who has a long track-record in construction ofBAC libraries, including making the BAC library for the human genome project. For organismsfor which interest is high to sequence the entire genome, 15X coverage is proposed. For others,10X coverage is proposed.

基因组 DNA 的大型插入文库是发育进化和遗传学比较研究的宝贵资源，可解决生物学中的基本问题，例如显示基因组已经进化以及基因组进化如何导致身体规划的进化。本研究的目标是构建代表后生动物广度的 11 个 BAC 文库。重点是占据对理解动物进化至关重要的系统发育位置的动物。优选具有作为发育模型生物体的潜力的生物体。因此，选择了两种后口动物：七鳃鳗和头索文昌鱼，前者位于颅骨的底部，对于理解脊椎动物进化过程中基因和染色体复制模式至关重要，后者是与脊椎动物最接近的现存无脊椎动物亲戚。在分子系统发育学的基础上，原口动物最近被分为两类：蜕皮动物门和冠轮动物门。然而，这些类群中每个门的分支模式都很难解决。由于蜕皮动物、果蝇和秀丽隐杆线虫的代表已被充分研究，我们没有选择任何蜕皮动物。对于一般来说在基因、发育和进化方面很少受到关注的轮轮动物门，选择了七种生物。其中包括 2 种环节动物，其中一种是多毛类 Platynereis dumerilii，在环节动物中相对处于基础地位，另一种是环节动物。其中，水蛭 HelobdellaRobusta 的衍生程度更高。Platynereis 正在迅速成为一种冠轮动物模型发育生物，并且虽然水蛭是相当衍生的，但多年来它一直是发育遗传学研究的对象。其中包括两种软体动物——一种双壳类（Spisula Solidissima）和一种腹足类（Ilyanassaobsoleta）。其他轮轮动物包括 1 种纽虫 (Cerebratulus milkeus)、1 种 sipunculid(Temiste langiformis) 和 1 种 acoel 扁虫 (Neochildea fusca)。无腔群体的系统发育地位是有争议的。根据形态学，它们被认为是基础两侧对称动物。然而，大多数（但不是全部）分子系统发育分析将无腔动物置于原口动物内。为了解决两侧对称动物的起源，我们选择了栉水母（Mnemiopsis leidyi）。最后，为了解决后生动物的起源问题，选择了海绵，Callyspongia diffusa，最基础后生动物的代表。 BAC 文库将由 P. de Jong（奥克兰儿童医院研究所）构建和分发，他在 BAC 文库构建方面有着长期的记录，包括为人类基因组计划制作 BAC 文库。对于对整个基因组进行测序的生物体，建议覆盖 15 倍。对于其他人，建议覆盖 10 倍。