Periodic variation of mutation rates in bacterial genomes associated with replication timing
Journal Article - Open Access
Indiana University at Bloomington Bloomington United States
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The causes and consequences of spatiotemporal variation in mutation rates remains to be explored in nearly all organisms. Here we examine relationships between local mutation rates and replication timing in three bacterial species whose genomes have multiple chromosomes Vibrio fischeri, Vibrio cholerae, and Burkholderia cenocepacia. Following five evolution experiments with these bacteria conducted in the near-absence of natural selection, the genomes of clones from each lineage were sequenced and analyzed to identify variation in mutation rates and spectra. In lineages lacking mismatch repair, base-substitution mutation rates vary in a mirrored wavelike pattern on opposing replichores of the large chromosome of V. fischeri and V. cholerae, where concurrently replicated regions experience similar base-substitution mutation rates.