R. Kassen

Unpredictability of the fitness effects of antimicrobial resistance mutations across environments in Escherichia coli

This study shows that the fitness effects of antimicrobial resistance mutations vary widely across genetic backgrounds and environments in Escherichia coli, challenging assumptions about their predictability.

Experimental evidence that network topology can accelerate the spread of beneficial mutations

The paper tests how network topology affects the spread of beneficial mutations in both simulated and experimental settings, finding that certain topologies increase fixation probability.

The Evolution and Fate of Diversity Under Hard and Soft Selection

This study examines how hard and soft selection affect genetic diversity maintenance under strong divergent selection, finding that soft selection better sustains diversity through negative frequency-dependent selection.

Genomics of experimental diversification of Pseudomonas aeruginosa in cystic fibrosis lung-like conditions

This study investigates genetic changes in Pseudomonas aeruginosa under CF-like conditions, finding that spatial structure reduces beneficial mutation supply and drives divergent evolution.

The distribution of fitness effects among synonymous mutations in a gene under selection

The paper estimates the distribution of fitness effects among synonymous mutations in a gene under selection and finds they can be deleterious or beneficial, similar to nonsynonymous mutations.

Rapid diversification of Pseudomonas aeruginosa in cystic fibrosis lung-like conditions

This study shows that nutritional conditions in CF lungs drive rapid diversification of Pseudomonas aeruginosa, leading to phenotypic and genetic variation that may contribute to chronic infection.

The emergence, maintenance and demise of diversity in a spatially variable antibiotic regime

This study shows spatially variable antibiotic use delays but does not prevent resistance spread, driven by fitness trade-offs between resistance and growth rate.