MOLECULAR PHYLOGENY OF EUKARYOTES

这个提议是关于系统发育起源的。 有细胞核的细胞 这些分子和超微结构的创新是什么， 允许其形成？谁是微生物的祖先 植物、动物和真菌的王国分类学的界限是什么 区分真核生物的主要类群以及它们之间是如何相互关联的？的 答案就在原生生物王国里，它的成员统治着 真核生物的进化史 最早期的有核细胞， 植物、动物和真菌的最后共同祖先是原生生物， 这个分类群不是一个紧密的进化组合。相反地， 它描述了组织的层次， 不能被明确地置于系统发育中的血统 语境运用传统的比较形态学、生理学 或生物化学。 分子系统学提供了新的机会， 收集客观的、定量的分析;可以使用的框架 解释不同分类群中的分子和结构相似性， 确定专性人类寄生虫的自由生活亲属，并设计 用于鉴定病原体的诊断性rRNA探针。 在过去 几年来，核糖体RNA编码区的比较 彻底改变了我们对真核生物进化的看法 而不是三 “高等王国”，有五个主要的复杂进化组合 几乎是同时分开的， 真核生物血统的进化史。 大规模 在系统辐射之前， 血统;有些像古细菌和真细菌一样古老， 血统. 最早的分支是以无线粒体的 寄生虫，其中许多导致人类疾病。 然而，信息 关于真核生物最深处的分支模式是最小的， 但仍有可能确定主要真核生物的分离顺序， 组 本提案的目标是构建一个定量的 真核生物的系统发育框架基于小的 亚单位核糖体RNA基因序列。

This proposal is about phylogenetic origins. Where did cells with nuclei come from and what are the molecular and ultrastructure innovations that permitted their formation? Who were the microbial ancestors to the higher kingdoms of plants, animals and fungi? What are the taxonomic boundaries separating major groups of eukaryotes and how are they interrelated? The answers lie within the kingdom Protista whose members dominated the evolutionary history of eukaryotes. The earliest cells with nuclei and the last common ancestor to plants, animals and fungi were protists, but this taxonomic group is not a cohesive evolutionary assemblage. Instead, it describes levels of organization and is represented by paraphyletic lines of descent that can not be definitively placed in a phylogenetic context using traditional methods of comparative morphology, physiology or biochemistry. Molecular systematics offer a new opportunity to assemble objective, quantitative phylogenies; frameworks that can be used to interpret molecular and structural similarities in divergent taxa, to identify free living relatives to obligate human parasites, and to design diagnostic rRNA probes for identification of pathogens. During the past few years, comparisons of ribosomal RNA coding regions have revolutionized our perspective on eukaryotic evolution. Instead of three "higher kingdoms", there are five major complex evolutionary assemblages that diverged nearly simultaneously and relatively late in the evolutionary history of the eukaryotic line of descent. The massive phyletic radiation was preceded by a progression of independent protist lineages; some as ancient as the archaebacterial and eubacterial lines of descent. The earliest branches are represented by amitochondrial parasites, many of which cause disease in humans. However information about the deepest eukaryotic branching patterns is minimal and it is not yet possible to identify the order of separation for the major eukaryotic groups. The goal of this proposal is construct a quantitative phylogenetic framework for eukaryotes based upon comparisons of small subunit ribosomal RNA gene sequences.