Gorgeous mosaic of mitochondrial genes created by horizontal transfer and gene conversion
Gorgeous mosaic of mitochondrial genes created by horizontal transfer and gene conversion
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DOI：
10.1073/pnas.1016295107
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发表时间：
2010-12-14
影响因子：
11.1
通讯作者：
Palmer, Jeffrey D.
中科院分区：
文献类型：
--
作者：
Hao, Weilong;Richardson, Aaron O.;Palmer, Jeffrey D.
水平基因转移（HGT）最著名的结果是引入新基因，但也描述了其他结果。当转移的基因在受体基因组中具有同源物时，天然基因可能被瞬时存在的外源DNA的基因转换功能性取代（并且随后丢失）或部分覆盖。在这里，我们报告的发现，在两个谱系的植物线粒体基因，新的基因组合，所产生的转换共存的本地和外国同源物。这些谱系在原生和外来拷贝之间经历了复杂的转换，在物种形成过程中，转换反复发生，差异很大，导致参与呼吸和内含子剪接的嵌合基因的辐射。基于这些研究结果，我们开发了一个模型，重复HGT和差异基因转换模型，集成HGT和正在进行的基因转换的背景下，物种形成。最后，我们表明，这些HGT驱动的基因转换辐射之一，遵循两个额外类型的转换嵌合体，即，线粒体内逆加工和细胞器间的基因转换跨越20亿年的线粒体和叶绿体之间的鸿沟。这些发现扩展了我们对HGT和基因转换作为创造性进化力量的理解，建立了植物线粒体作为研究HGT及其遗传反应的进化动力学的首要系统，并建议仔细检查细菌和其他基因组中类似的，可能被忽视的现象。
The best known outcome of horizontal gene transfer (HGT) is the introduction of novel genes, but other outcomes have been described. When a transferred gene has a homolog in the recipient genome, the native gene may be functionally replaced (and subsequently lost) or partially overwritten by gene conversion with transiently present foreign DNA. Here we report the discovery, in two lineages of plant mitochondrial genes, of novel gene combinations that arose by conversion between coresident native and foreign homologs. These lineages have undergone intricate conversion between native and foreign copies, with conversion occurring repeatedly and differentially over the course of speciation, leading to radiations of mosaic genes involved in respiration and intron splicing. Based on these findings, we develop a model-the duplicative HGT and differential gene conversion model-that integrates HGT and ongoing gene conversion in the context of speciation. Finally, we show that one of these HGT-driven gene-conversional radiations followed two additional types of conversional chimerism, namely, intramitochondrial retroprocessing and interorganellar gene conversion across the 2 billion year divide between mitochondria and chloroplasts. These findings expand our appreciation of HGT and gene conversion as creative evolutionary forces, establish plant mitochondria as a premiere system for studying the evolutionary dynamics of HGT and its genetic reverberations, and recommend careful examination of bacterial and other genomes for similar, likely overlooked phenomena.