In Vitro Molecular Evolution of RNA Entirely Consisting of Prebiotic Materials on the Simulated Primitive Earth

核酶的发现提出了RNA世界假说，即RNA分子在原始生命中起着核心作用。此外，RNA适体和核酶的体外选择技术支持了在原始地球条件下可以产生许多功能性RNA分子的可能性。然而，体外选择技术需要人工分子生物学工具和设备。因此，RNA分子可以通过类似体外选择技术的进化系统产生的可能性必须用完全原始的材料来阐明，无论这种进化系统是否可能在原始的地球条件下产生。我们本研究的最终目标是建立一个完全由原始物质构建的进化系统，并从许多RNA分子中确定基于RNA的类生命系统的化学进化途径。从RNA分子到基于RNA的类生命系统的进化包括以下4个步骤：(1)原始地球下RNA的自发形成，(2)RNA分子的复制，(3)RNA分子的扩增，(4)RNA分子的自然选择。在本研究中，我们试图为每个步骤找到有效的途径和条件，以将每个步骤结合为达尔文进化过程。我们证实了粘土矿物对(1)的催化反应可以形成由4个碱基组成的随机RNA分子序列。在第(4)步中发现，RNA分子的自然选择可以在高温下从随机混合的RNA序列中发生。我们还试图在没有模板DNA和酶的情况下找到步骤(3)和(4)的有效途径和条件。虽然我们目前还没有发现在原始地球条件下RNA复制的有效途径，但我们观察到寡核苷酸模板与添加剂可以增强寡核苷酸的形成。少

Discovery of ribozyme suggested the RNA world hypothesis, where RNA molecules played a central role in the primitive life. In addition, in vitro selection technique for RNA aptamers and ribozymes supported the possibility that a number of functional RNA molecules can be created under the primitive earth conditions. However, the in vitro selection technique requires artificial molecular biological tools and equipment. Thus, the possibility that RNA molecules could have been created through an evolutionary system like the in vitro selection technique must be elucidated using entirely primitive materials whether such evolutionary system could have be under the primitive earth condition. Our final goal of the present study is to make an evolutionary system, which is entirely constructed from only primitive materials and determine the pathway of chemical evolution of an RNA-based life-like system from a number of RNA molecules. The evolution of an RNA-based life-like system from RNA molecul … More es consists of the following 4 steps; (1) spontaneous formation of RNA under the primitive earth, (2) replication of the RNA molecules, (3) amplification of the RNA molecules, (4) natural selection of the RNA molecules. In the present study, we attempted to find efficient pathways and conditions for each step to combine each step as a Darwinian evolutionary process. We confirmed that random sequences of RNA molecules consisting of 4 bases can be formed by clay mineral catalytic reaction regarding (1). It was found regarding (4) step that natural selection of RNA molecules could have occurred at high temperatures from random mixed sequences of RNA. We also attempted to find efficient pathways and conditions for step (3) and (4) in the absence of template DNA and enzymes. Although we have not yet found an efficient pathway for replication of RNA under the primitive earth conditions at the present time, we observed an enhancement of oligonucleotide formation directed by oligonucleotide template with an additive. Less