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10.1016-j.jtbi.2021.110822 |
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220427s2021 CNT 000 0 und d |
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|a 00225193 (ISSN)
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|a Rolling-circle and strand-displacement mechanisms for non-enzymatic RNA replication at the time of the origin of life
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|b Academic Press
|c 2021
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|z View Fulltext in Publisher
|u https://doi.org/10.1016/j.jtbi.2021.110822
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|a It is likely that RNA replication began non-enzymatically, and that polymerases were later selected to speed up the process. We consider replication mechanisms in modern viruses and ask which of these is possible non-enzymatically, using mathematical models and experimental data found in the literature to estimate rates of RNA synthesis and replication. Replication via alternating plus and minus strands is found in some single-stranded RNA viruses. However, if this occurred non-enzymatically it would lead to double-stranded RNA that would not separate. With some form of environmental cycling, such as temperature, salinity, or pH cycling, double-stranded RNA can be melted to form single-stranded RNA, although re-annealing of existing strands would then occur much faster than synthesis of new strands. We show that re-annealing blocks this form of replication at a very low concentration of strands. Other kinds of viruses synthesize linear double strands from single strands and then make new single strands from double strands via strand-displacement. This does not require environmental cycling and is not blocked by re-annealing. However, under non-enzymatic conditions, if strand-displacement occurs from a linear template, we expect the incomplete new strand to be almost always displaced by the tail end of the old strand through toehold-mediated displacement. A third kind of replication in viruses and viroids is rolling-circle replication which occurs via strand-displacement on a circular template. Rolling-circle replication does not require environmental cycling and is not prevented by toehold-mediated displacement. Rolling-circle replication is therefore expected to occur non-enzymatically and is a likely starting point for the evolution of polymerase-catalysed replication. © 2021 The Author(s)
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|a catalysis
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|a displacement
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|a DNA replication
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|a DNA Replication
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|a enzyme activity
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|a evolution
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|a genetic recombination
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|a Non-enzymatic template-directed replication
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|a origin of life
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|a Origin of Life
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|a polymerase chain reaction
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|a Recombination, Genetic
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|a RNA
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|a RNA
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|a RNA
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|a RNA viruses
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|a RNA World
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|a Rolling circle
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|a Strand-displacement
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|a Viroids
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|a Higgs, P.G.
|e author
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|a Tupper, A.S.
|e author
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|t Journal of Theoretical Biology
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