Speaker
Description
Mutation rates vary within genomes, leading to biases in the genetic change that fuels evolution. Some regions have extreme rates of mutation and are referred to as mutational ‘hotspots’. Understanding the causes of hotspots are important if evolutionary biology is to become a more predictive science. We have taken advantage of a chance observation to show that genetic regulation can influence mutation rates inside a promoter. While performing experiments with the bacterium Pseudomonas fluorescens, we observed near deterministic levels of parallel evolution caused by an identical point mutation inside the highly conserved promoter of rpoS. We have shown this promoter has a mutational hotspot, with transcriptional regulatory proteins required for maximisation of mutation rate (~5000-fold above expectation). This talk will present evidence for this transcription-dependent hotspot, explore the conditions under which similar hotspots might appear in other promoters and organisms, and discusses the ecological and evolutionary consequences of promoter-located hotspots.
