Asymmetric Context-Dependent Mutation Patterns Revealed through Mutation-Accumulation Experiments.
Mol Biol Evol
; 32(7): 1672-83, 2015 Jul.
Article
em En
| MEDLINE
| ID: mdl-25750180
ABSTRACT
Despite the general assumption that site-specific mutation rates are independent of the local sequence context, a growing body of evidence suggests otherwise. To further examine context-dependent patterns of mutation, we amassed 5,645 spontaneous mutations in wild- type (WT) and mismatch-repair deficient (MMR(-)) mutation-accumulation (MA) lines of the gram-positive model organism Bacillus subtilis. We then analyzed>7,500 spontaneous base-substitution mutations across B. subtilis, Escherichia coli, and Mesoplasma florum WT and MMR(-) MA lines, finding a context-dependent mutation pattern that is asymmetric around the origin of replication. Different neighboring nucleotides can alter site-specific mutation rates by as much as 75-fold, with sites neighboring GC base pairs or dimers involving alternating pyrimidine-purine and purine-pyrimidine nucleotides having significantly elevated mutation rates. The influence of context-dependent mutation on genome architecture is strongest in M. florum, consistent with the reduced efficiency of selection in organisms with low effective population size. If not properly accounted for, the disparities arising from patterns of context-dependent mutation can significantly influence interpretations of positive and purifying selection.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bactérias
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Reparo de Erro de Pareamento de DNA
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Taxa de Mutação
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Acúmulo de Mutações
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Mol Biol Evol
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2015
Tipo de documento:
Article