Institute for Applied Mathematics and Systems Research (IIMAS), National Autonomous University of Mexico (UNAM), Mexico City, 04510, Mexico.
Center for the Sciences of Complexity (C3), National Autonomous University of Mexico (UNAM), Mexico City, 04510, Mexico.
Sci Rep. 2018 Feb 23;8(1):3532. doi: 10.1038/s41598-018-21973-y.
Theories of the origin of the genetic code typically appeal to natural selection and/or mutation of hereditable traits to explain its regularities and error robustness, yet the present translation system presupposes high-fidelity replication. Woese's solution to this bootstrapping problem was to assume that code optimization had played a key role in reducing the effect of errors caused by the early translation system. He further conjectured that initially evolution was dominated by horizontal exchange of cellular components among loosely organized protocells ("progenotes"), rather than by vertical transmission of genes. Here we simulated such communal evolution based on horizontal transfer of code fragments, possibly involving pairs of tRNAs and their cognate aminoacyl tRNA synthetases or a precursor tRNA ribozyme capable of catalysing its own aminoacylation, by using an iterated learning model. This is the first model to confirm Woese's conjecture that regularity, optimality, and (near) universality could have emerged via horizontal interactions alone.
遗传密码起源的理论通常诉诸于自然选择和/或可遗传特征的突变，以解释其规律性和容错稳健性，然而目前的翻译系统预设了高保真复制。Woese 对这个启动问题的解决方案是假设代码优化在降低早期翻译系统引起的错误的影响方面发挥了关键作用。他进一步推测，最初的进化主要是由松散组织的原细胞（“原核生物”）之间的细胞成分的水平交换所主导，而不是由基因的垂直传递所主导。在这里，我们基于码片段的水平转移，使用迭代学习模型，模拟了这种共进化。这是第一个模型，它证实了 Woese 的推测，即规律性、最优性和（近乎）普遍性仅通过水平相互作用就可以出现。
