The two ages of the RNA world, and the transition to the DNA world: a story of viruses and cells
The two ages of the RNA world, and the transition to the DNA world: a story of viruses and cells
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DOI：
10.1016/j.biochi.2005.03.015
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发表时间：
2005-09-01
期刊：
影响因子：
3.9
通讯作者：
Forterre, P
中科院分区：
文献类型：
--
作者：
Forterre, P
大多数进化论者同意认为，我们现在的RNA/DNA/蛋白质世界起源于一个更简单的世界，在这个世界中，RNA既扮演了催化剂的角色，又扮演了遗传物质的角色。结构研究和比较基因组学的最新发现现在让人们对这种转变有了更清晰的了解。这些数据表明，进化经历了几个步骤，首先是从RNA到RNA/蛋白质世界(定义了RNA世界的两个时代)，最后是以DNA为基础的当今世界。DNA世界本身可能起源于两个步骤，首先是核糖核苷酸还原酶发明后的U-DNA世界，然后是T-DNA世界，独立发明了至少两种胸苷合成酶。最近，几位作者提出，从RNA世界到最后的通用细胞祖先(LUCA)的进化可能发生在细胞发明之前。相反，我在这里认为，RNA世界的进化发生在细胞和病毒(捕食者、捕食者和共生体)相互竞争的框架内。我把重点放在了从RNA到DNA的转变上，并扩展了我之前的假设，即病毒在DNA的出现中发挥了关键作用。DNA及其相关机制(复制、修复、重组)首先在感染RNA细胞的DNA病毒世界中进化和多样化的假设很容易解释病毒编码的DNA交易蛋白的存在而没有细胞同源。它还可能解释比较基因组学中令人费解的观察结果，例如细胞世界中存在两个不同源的DNA复制机制。我在这里建议一种将DNA从病毒转移到细胞的具体方案，并简要探索这种类型的几次独立转移产生两种细胞类型(原核生物/真核生物)和目前已知的三个细胞域(古生菌、细菌和真核生物)的有趣可能性。(C)2005年爱思唯尔集团。版权所有。
Most evolutionists agree to consider that our present RNA/DNA/protein world has originated from a simpler world in which RNA played both the role of catalyst and genetic material. Recent findings from structural studies and comparative genomics now allow to get a clearer picture of this transition. These data suggest that evolution occurred in several steps, first from an RNA to an RNA/protein world (defining two ages of the RNA world) and finally to the present world based on DNA. The DNA world itself probably originated in two steps, first the U-DNA world, following the invention of ribonucleotide reductase, and later on the T-DNA world, with the independent invention of at least two thymidylate synthases. Recently, several authors have suggested that evolution from the RNA world up to the Last Universal Cellular Ancestor (LUCA) could have occurred before the invention of cells. On the contrary, I argue here that evolution of the RNA world taken place in a framework of competing cells and viruses (preys, predators and symbionts). I focus on the RNA-to-DNA transition and expand my previous hypothesis that viruses played a critical role in the emergence of DNA. The hypothesis that DNA and associated mechanisms (replication, repair, recombination) first evolved and diversified in a world of DNA viruses infecting RNA cells readily explains the existence of viral-encoded DNA transaction proteins without cellular homologues. It also potentially explains puzzling observations from comparative genomic, such as the existence of two non-homologous DNA replication machineries in the cellular world. I suggest here a specific scenario for the transfer of DNA from viruses to cells and briefly explore the intriguing possibility that several independent transfers of this kind produced the two cell types (prokaryote/eukaryote) and the three cellular domains presently known (Archaea, Bacteria and Eukarya). (C) 2005 Elsevier SAS. All rights reserved.