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Ribosomal mosaicism in the archaebacterial eocytes.

机译：考古细菌细胞中的核糖体镶嵌。

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摘要

Ribosomal genes are used to construct evolutionary hypotheses regarding prokaryotic relationships. These relationships are then used to guide taxonomic classification. Central to the use of ribosomal genes in this capacity are the assumptions that these genes evolve in a tree-like manner and never undergo horizontal gene transfer. Various examples within the body of published research contradict these assumptions, suggest that horizontal transfer does occur and furthermore results in mosaic ribosomal RNA genes. The research that is presented in this dissertation was undertaken in order to document the incidence and gauge the extent of horizontal transfer of ribosomal genes among a particular group of organisms, the hyperthermophilic archaebacterial eocytes (Crenarchaeota).;Horizontal transfer of ribosomal RNA genes was inferred from detecting recombination between ribosomal RNA genes from different taxa. For a small case example, it was shown that the spatial partition of the alignment corresponds to unique and well-supported phylogenetic signals. Bulk analyses provided evidence that extensive horizontal transfer has occurred during the evolutionary history of the ribosomal RNA genes possessed by the majority of cultivated archaebacterial eocytes. Ribosomal proteins were also shown to undergo frequent horizontal transfer, with at most five out of twenty eight ribosomal proteins sharing a pathway through the ancestral population that gave rise to the modern day eocytes.;These results make it clear that the ribosome as a whole does not evolve according to a strict tree-like process. Instead, frequent exchange of ribosomal components gives rise to a population structure for this ubiquitous and essential molecular machine. As such, care should be undertaken when interpreting phylogenies calculated using ribosomal genes. Rather than providing evidence of relatedness by vertical descent, these phylogenies may instead be placing taxa together that have undergone recent ribosomal gene exchange.
机译：核糖体基因用于构建有关原核生物关系的进化假设。然后将这些关系用于指导分类学分类。假定核糖体基因以这种能力进化的前提是这些基因以树状方式进化且从未经历水平基因转移。已发表的研究体内的各种例子都与这些假设相矛盾，表明确实发生了水平转移，并进一步导致了镶嵌核糖体RNA基因的产生。本文进行的研究是为了记录核糖体基因在特定生物群中的发生率和水平转移的程度，即特定的生物体，即嗜热古细菌性Eocytes（Crenarchaeota）。；推断出核糖体RNA基因的水平转移检测不同分类单元的核糖体RNA基因之间的重组。对于一个小案例，已显示该比对的空间划分对应于唯一且得到良好支持的系统发育信号。大量分析提供的证据表明，在大多数培养的古细菌单核细胞所拥有的核糖体RNA基因的进化过程中，发生了广泛的水平转移。核糖体蛋白还显示出频繁的水平转移，在28个核糖体蛋白中至多有5个共享通过祖先群体的途径，从而产生了现代的细胞。这些结果表明，核糖体作为一个整体确实可以不能按照严格的树状过程进化。取而代之的是，核糖体成分的频繁交换导致了这种普遍存在且必不可少的分子机器的种群结构。因此，在解释使用核糖体基因计算的系统发育时，应格外小心。这些系统发育谱可能不是通过垂直后裔提供相关性的证据，而是将最近经历了核糖体基因交换的分类单元放在一起。

著录项

  • 作者

    Herbold, Craig William.;

  • 作者单位

    University of California, Los Angeles.;

  • 授予单位 University of California, Los Angeles.;
  • 学科 Biology Genetics.;Biology Bioinformatics.;Biology Evolution and Development.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 212 p.
  • 总页数 212
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

  • 入库时间 2022-08-17 11:38:30

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