Archives SEEM

12 mars 2021, 11h30 (diffusion en visioconférence).

Evolutionary consequences of biased mutation rates

Alejandro Couce

Link to seminar: https://umontpellier-fr.zoom.us/webinar/register/WN_RjqF9JyeRzC5mjWETOfvlA

Evolutionary Systems Genetics of Microbes Lab
Centre for Plant Biotechnology and Genomics (CBGP, UPM-INIA)
Technical University of Madrid, Spain

http://www.cbgp.upm.es/index.php/es/informacion-cientifica/csbgp/alejandro-couce

Cells across all domains of life vary on their propensity to experience different types of mutations, an idiosyncrasy that arises from the physico-chemical properties of DNA and its associated replication and repair machinery. But, are these mutation biases of any consequence? Population genomics evidence suggests that these biases may underlie natural polymorphisms in humans and other vertebrates. More direct demonstrations of their evolutionary significance come from studies with bacterial strains defective in mutation-prevention systems. These bacterial hypermutators are commonly isolated in clinical settings, where their highly elevated (yet highly biased) mutation rate constitutes a successful strategy to withstand environmental challenges, such as antibiotics. In this talk, I will discuss the degree to which mutational biases do matter for our understanding of various aspects of microbial evolution; presenting evidence of their importance in driving populations towards divergent adaptive paths, shaping the evolution of genome size and composition across bacteria, and determining the very evolution of mutation rate itself.

Recent publications:

1. COUCE & TENAILLON. Mutation bias and GC content shape antimutator invasions. Nature Communications, 10 (2019).

2. COUCE, et al. Mutator genomes decay, despite sustained fitness gains, in a long-term experiment with bacteria. PNAS, 114 (2017).

3. COUCE, et al. Bypass of genetic constraints during mutator evolution to antibiotic resistance. Procs Roy. Soc. B, 282 (2015).