High mutation rate evolution during adaptation to two types of stress

December 11th, 2019 - 10:30AM

Stéphanie Bedhomme, CEFE CNRS Montpellier (France)

Abstract: 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.

Location: LCQB Kitchen, building C, 4th floor, Pierre et Marie Curie Campus

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Seminar organised by the Laboratory of Computational and Quantitative Biology