Mutation frequency

Term in genetics that defines the proportion of mutants (averaged for an entire sequence or specific to a particular site) in a genome population.

Replication mutations can be either base substitutions, base additions or base deletions. When discussing mutations, a distinction must be made between mutation frequency and mutation rate. The mutation rate is the frequency of occurrence of a mutation event during genome replication.

The frequency of mutation errors depends on the type of replication, the context of the nucleotide sequence and environmental factors. For example, nucleic acids that replicate via DNA have much lower mutation rates than those that replicate via other pathways. This is because DNA-dependent DNA polymerase has a proofreading function that checks whether the correct nucleotide has been added, whereas the other polymerases (DNA-dependent RNA polymerase, RdRp and RT) do not.