PT  - JOURNAL ARTICLE
AU  - Merrikh, Christopher N.
AU  - Harris, Leonard A.
AU  - Mangiameli, Sarah
AU  - Merrikh, Houra
TI  - Replication-transcription conflicts promote adaptive evolution
AID  - 10.1101/2020.06.23.167650
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.23.167650
4099  - http://biorxiv.org/content/early/2020/06/25/2020.06.23.167650.short
4100  - http://biorxiv.org/content/early/2020/06/25/2020.06.23.167650.full
AB  - In 2013, we discovered that encounters between the replication and transcription machineries allow bacteria to evolve at an accelerated rate by promoting mutagenesis in lagging strand genes. Though we proposed that this process is adaptive, it is also possible that the increased mutation frequency in lagging strand genes could be the result of reduced purifying selection (neutral selection).Due to the low number of available genome sequences at the time of publication, we were unable to distinguish between these two models with a high level of confidence. Here, we utilized the wealth of newly available bacterial genome sequences to examine these two possibilities. To test the adaptive hypothesis, we analyzed convergent mutation patterns. To test the neutral hypothesis, we performed in silico modeling. Our results clearly demonstrate that the neutral model cannot explain the increased mutagenesis of lagging strand genes. Additionally, our evolutionary convergence data strongly support the adaptive hypothesis. We conclude that encounters between the replication and transcription machineries in lagging strand gene accelerate the discovery of beneficial mutations.Competing Interest StatementThe authors have declared no competing interest.