The Ionian School, Genetic Code and tRNA Origin Laboratory, Via Roma 19, 67030, Alfedena (L'Aquila), Italy; Institute of Biosciences and Bioresources, National Research Council, Via P. Castellino, 111, 80131, Naples, Italy.
Biosystems. 2021 Apr;202:104330. doi: 10.1016/j.biosystems.2020.104330. Epub 2020 Dec 19.
It has been firmly observed that replicative DNA polymerases of bacteria, archaea and eukaryotes are not homologous proteins. This lack of homology in the replication apparatus among the domains of life is not only compatible with but would seem to imply the view that the emergence of DNA occurred in the fundamental cellular lineages. In consequence, this diversity of DNA polymerase would go back to the level of ancestors of the domains of life and to the evolutionary time in which the DNA emerged. Therefore, the presumed evolutionary stage linked to the RNA- > DNA transition would have occurred only at the level of ancestors of the main lineages of the tree of life. Thus, the high noise associated with this major evolutionary transition and the impossibility for a cellular stage to generate different fundamental genetically profound traits - such as the different replication apparatuses of bacteria, archaea and eukaryotes - would imply not only that the last universal common ancestor (LUCA) was a progenote but that the ancestors of the domains of life were also at this evolutionary stage. So, I criticize the hypotheses which want, instead, that completely different cells - such as, bacteria and archaea - could have originated from a cellular LUCA.
人们已经明确观察到，细菌、古菌和真核生物的复制 DNA 聚合酶不是同源蛋白。生命领域的复制装置之间缺乏同源性不仅与这样的观点是一致的，即 DNA 的出现是在基本的细胞谱系中发生的，而且似乎还暗示了这一点。因此，这种 DNA 聚合酶的多样性可以追溯到生命领域的祖先和 DNA 出现的进化时期。因此，与 RNA->DNA 转变相关的假定进化阶段只发生在生命之树的主要谱系的祖先中。因此，这种主要进化转变所带来的高噪声，以及细胞阶段不可能产生不同的、具有深远遗传意义的基本特征——例如细菌、古菌和真核生物的不同复制装置——不仅意味着最后一个普遍共同祖先（LUCA）是一个前细胞体，而且生命领域的祖先也处于这个进化阶段。因此，我批评了那些希望完全不同的细胞——如细菌和古菌——可以从一个细胞 LUCA 起源的假说。
