Origin of DNA replication is an enigma because the replicative DNA polymerases (DNAPs) are not homologous among the three domains of life, Bacteria, Archaea, and Eukarya. The homology between the archaeal replicative DNAP (PolD) and the large subunits of the universal RNA polymerase (RNAP) responsible for transcription suggests a parsimonious evolutionary scenario. Under this model, RNAPs and replicative DNAPs evolved from a common ancestor that functioned as an RNA-dependent RNA polymerase in the RNA-protein world that predated the advent of DNA replication. The replicative DNAP of the Last Universal Cellular Ancestor (LUCA) would be the ancestor of the archaeal PolD.

中文翻译：

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LUCA 的复制机制：DNA 复制和转录的共同起点。


DNA 复制的起源是一个谜，因为复制 DNA 聚合酶 (DNAP) 在细菌、古细菌和真核生物这三个生命域中并不同源。古细菌复制 DNAP (PolD) 和负责转录的通用 RNA 聚合酶 (RNAP) 大亚基之间的同源性表明了一种简约的进化场景。在这个模型下，RNAP 和复制性 DNAP 是从一个共同的祖先进化而来的，它们在 DNA 复制出现之前就在 RNA 蛋白质世界中充当 RNA 依赖性 RNA 聚合酶。最后的通用细胞祖先 (LUCA) 的复制 DNAP 将是古细菌 PolD 的祖先。