Competition between bridged dinucleotides and activated mononucleotides determines the error frequency of nonenzymatic RNA primer extension

Abstract Nonenzymatic copying of RNA templates with activated nucleotides is a useful model for studying the emergence heredity at origin life. Previous experiments defined-sequence have pointed to poor fidelity primer extension as major problem. Here we examine mismatches during on random in simultaneous presence all four 2-aminoimidazole-activated nucleotides. Using deep sequencing approach that reports millions individual template-product pairs, are able correct and incorrect polymerization function sequence context. We previously shown predominant pathway involves reaction imidazolium-bridged dinucleotides, which form spontaneously by two mononucleotides each other. now show sequences correctly paired products reveal patterns expected from bridged dinucleotide mechanism, whereas those associated consistent direct mononucleotides. Increasing ratio dinucleotides mononucleotides, either using purified components or isocyanide-based activation chemistry, reduces error frequency. Our results point testable strategies accurate nonenzymatic arbitrary sequences.