Fitness effects of mutations depend on environmental parameters. For example, mutations that increase fitness of bacteria at high antibiotic concentration often decrease fitness in the absence of antibiotic, exemplifying a tradeoff between adaptation to environmental extremes. We develop a mathematical model for fitness landscapes generated by such tradeoffs, based on experiments that determine the antibiotic dose-response curves of Escherichia coli strains, and previous observations on antibiotic resistance mutations. Our model generates a succession of landscapes with predictable properties as antibiotic concentration is varied. The landscape is nearly smooth at low and high concentrations, but the tradeoff induces a high ruggedness at intermediate antibiotic concentrations. Despite this high ruggedness, however, all the fitness maxima in the landscapes are evolutionarily accessible from the wild type. This implies that selection for antibiotic resistance in multiple mutational steps is relatively facile despite the complexity of the underlying landscape.
Experimental data have been deposited in Edinburgh DataShare
Experimental data for the article Predictable Properties of Fitness Landscapes Induced by Adaptational TradeoffsEdinburgh DataShare, 10.7488/ds/2756.
Data from: Interplay in the Selection of Fluoroquinolone Resistance and Bacterial FitnessPLOS Pathogens, 10.1371/journal.ppat.1000541.
- Joachim Krug
- Rosalind J Allen
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Richard A Neher, University of Basel, Switzerland
© 2020, Das et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.