Insertions and deletions (indels) are prone to being formed at short sequence repeats owing to the misalignment of the DNA strands during replication, and a similar mechanism allows them to be bypassed in both transcription and translation. A recent study has investigated how well indels are tolerated in evolution as a result of transcriptional and translational bypassing. To identify how frequently these mutations occur, the authors mutated the Haemophilus aegyptius M.HaeIII gene in vitro using an error-prone polymerase followed by sequencing. They then expressed these mutated genes in Escherichia coli to ascertain the effect of natural selection. They found that the longer the repeats in M.HaeIII, the more frequently the mutations were formed and maintained in the E. coli population and were hence tolerated.