ACCELERATED EVOLUTION OF PLANT MITOCHONDRIAL DNA

植物线粒体 DNA 的加速进化

• 批准号: 2518871
• 负责人: CHRISTOPHER L PARKINSON
• 金额: $ 2.62万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-27 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2518871
• 关键词: biochemical evolution; introns; mitochondrial DNA; molecular genetics; plant genetics; plant proteins; posttranscriptional RNA processing

Mitochondrial genomes have undergone massive reductions in size and gene content since their endosymbiotic origin. Furthermore, compared with the genomes of their bacterial ancestors, most mitochondrial DNA lineages evolve rapidly in sequence. Land plants are apparently the one exception to this, but we have very recently identified two independent lineages of plants (Pelargonium and Plantago) whose substitution rates for four mitochondrial protein and two rRNA genes are at least 5-30 times higher than those of typical, slowly-evolving plant mitochondrial genomes. Hypotheses for the mechanisms underlying these major and recent increases in mitochondrial DNA mutation rate include: 1) deficient DNA repair, 2) error-prone DNA replication, and 3) error-prone retroprocessing. Although virtually all plant mitochondrial mRNAs are subject to extensive RNA editing, our data indicate that mitochondrial RNA editing does not occur in either Pelargonium or Plantago, that in fact their genomes are already edited as a consequence of unusually extensive retroprocessing. These data support the hypothesis of intense, error-prone retroprocessing, i.e., mutagenic reverse transcription followed by recombination back into the genome. Experiments are proposed to test among the various hypotheses and to determine the mechanisms responsible for the observed acceleration in mitochondrial DNA evolution in Pelargonium and Plantago.

线粒体基因组的大小和基因大规模减少 自从其内共生起源以来的内容。 此外，与 细菌祖先的基因组，大多数线粒体DNA 谱系序列迅速发展。 土地植物显然是 除此之外，但我们最近已经确定了两个独立的 植物的谱系（Pelargonium和Plantago）的替代率 对于四个线粒体蛋白和两个rRNA基因至少为5-30 高于典型，缓慢发展的植物线粒体的次数 基因组。 假设这些主要的机制和 线粒体DNA突变率的最新增加包括：1） 不足的DNA修复，2）容易出错的DNA复制，3）容易出错 重新加入。 尽管几乎所有植物线粒体mRNA都是 根据大量的RNA编辑，我们的数据表明线粒体 RNA编辑都不发生在Pelargonium或Plantago中， 事实实际上，由于异常而编辑它们的基因组 广泛的重新加密。 这些数据支持 强烈的，容易出错的重新加工，即诱变反向 转录随后重组回到基因组中。 提出了实验来测试各种假设和TO 确定负责观察到加速度的机制 线粒体DNA的进化，骨根和植物学。