Speaker
Stephanie Bedhomme
Description
The drastic increase in mutation rate due to hyper-mutator genotype
has been shown to be favoured when a population is adapting to
stressful conditions. This is because they allow a faster provision of
beneficial mutations and hitchhike with the adaptive mutations they
have triggered. Here, we use an Escherichia coli strain with a high
probability of becoming hypermutator to investigate whether the nature
of the stress and its intensity have an effect on the selection of
hypermutator genotypes. To do so, we experimentally evolved E. coli
populations across a gradient of salinity and of subinhibitory
concentration of gentamicin. We show that the nature of the stress and
the associated target size for adaptive mutation strongly influences the
probability for a population to become hyper-mutator. We then
decipher the similarities and differences in the molecular bases of
adaption for hyper-mutator and wild-type genotypes.
Primary author
Stephanie Bedhomme
