Earth, a planetary PCR machine to create life, or the brief history of a tRNA

Abstract About 4 billion years ago, the Earth probably fulfilled the environmental conditions necessary to favour the transition from primitive chemistry to life. Based on a theoretical hairpin duplication origin of tRNAs and its putative peptide-coding capability before ribosomes existed, I postulate here that, in this hypothetical environment, Earth's daily temperature cycles could have provided a unique planetary ‘PCR machine’ to create self-replicating RNA hairpins that simultaneously templated amino acid polymerization in a primordial ‘PCR well’ of prebiotic molecules. This early RNA hairpin-peptide interaction could have established a reciprocal nucleopeptide replicator that paved the way for catalytic translation and replication machineries towards the origin of LUCA.