A mechanism for the strong beneficial effect of a synonymous substitution in an essential gene

Synonymous mutations are changes in the DNA that do not affect the protein sequence. Although often referred to as silent mutations, evidence suggests that synonymous mutations can affect gene expression, mRNA stability, protein stability, and even translation efficiency. While it has been shown that synonymous mutations can impact phenotype, less is known about the molecular mechanisms and potential of beneficial or adaptive effects of such changes within evolved populations. We report a beneficial synonymous mutation acquired via experimental evolution in an essential gene variant encoding the translation Elongation Factor protein EF-Tu.