∞ generated and posted on 2020.12.17 ∞

Post nucleotide insertion step during DNA replication in which the resulting base pairing is checked for accuracy, with the newly added nucleotide replaced if need be.

Proofreading is a key component of the accuracy of templated nucleic acid duplication and in fact is occasionally seen with RNA templated duplication as well, e.g., coronaviruses.

Proofreading represents one of a number of layers that contribute to the fidelity of DNA replication, that is, the low base misincorporation rates usually seen along with the low mutation rates generally observed.

The following video is a nice, short introduction to proofreading, though it does turn into an advertisement around 1:02:

Proofreading is notably mostly absent during RNA polymerization, greatly contributing to the error rates associated with that process, as most notably seen with RNA viruses such as HIV, i.e., human immunodeficiency virus, the cause of AIDS. That is, RNA-based genetic material tends to be riddled in duplication errors which are associated, in part, to the lack of proofreading among RNA polymerases as well as reverse transcriptases.