mutation rate

Term in genetics that defines the number of mismatches per copied nucleotide, regardless of the fate (increase or decrease in frequency) of the error copy generated.

A mutation rate for a genomic site measures a biochemical event that is determined by the replication machinery and environmental parameters. In contrast, a mutant or mutation frequency describes the proportion of a mutant or group of mutants in a genome population.

The frequency of a mutation depends on the rate at which it is generated (given by the mutation rate) and on its replication capacity relative to other genomes in the population. A particular mutation may be generated at a modest rate, but then occur at a high frequency because the mutation is advantageous for replication in that environment. The reverse can also occur. Some mutation hotspots (in the sense of genomic locations where mutations are most likely to occur) may never be included in the repertoire of the genomes present in a genome.

repertoire of mutations found in a genome population because they cause a selective disadvantage to the genome that harbors them.