The importance of genes does not predict their mutation rate.

In wild-type Escherichia coli, between-gene differences in mutational density are not predicted by gene “importance” (protein level or essentiality) or by replication strand, with no strand-linked mutation-rate differences detected.

• Why it matters: Claims that selection shapes mutation rates across genes—protecting important genes and elevating mutation rates for rapidly adapting ones—have been disputed by replication failures and analyses that may ignore covariates or rely on mismatch repair knockout data.
• What they did: Using amassed mutation-accumulation data from wild-type Escherichia coli and Saccharomyces cerevisiae, the authors ran multiple parameter-controlled analyses predicting mutational density while accounting for covariates and testing protein level, essentiality, and (in E. coli) replication strand via deviations from trinucleotide-controlled expectations.
• The result: In E. coli, more highly transcribed genes show only slightly lower mutation rates, but protein abundance and essentiality do not predict lower mutation density, strand effects are absent, and similar lack of support appears in yeast.

AI summary of the abstract · may contain errors · not medical advice · read the paper.