Host-parasite coevolution promotes innovation through deformations in fitness landscapes

During the struggle for survival, populations occasionally evolve new functions that give them access to untapped ecological opportunities. Theory suggests that coevolution between species can promote the evolution of such innovations by deforming fitness landscapes in ways that open new adaptive pathways. We directly tested this idea by using high throughput gene editing-phenotyping technology (MAGE-Seq) to measure the fitness landscape of a virus, bacteriophage λ, as it coevolved with its host, the bacterium Escherichia coli. Through computer simulations of λ’s evolution on the empirical fitness landscape, we showed that λ was more likely to evolve to use a new receptor if it experienced a shift in its fitness landscape caused by coevolution. Detailed examination of a single coevolving laboratory population showed that the first mutation λ evolved required the presence of the ancestral host, whereas later steps in λ’s evolution required the shift to a resistant host. When replays of t..., , , # Title of Dataset Host-parasite coevolution promotes innovation through deformations in fitness landscapes [Access this dataset on Dryad](https://doi.org/10.5061/dryad.ht76hdrhq) ## Description of the data and file structure * 'Simulation_results.xlsx' contains data for simulation results of frequency of OmpF-use evolution observed in different conditions. This data was used to construct Figure 2 (first sheet in the file) and Figure 2—figure supplement 2 (rest of the sheets). Sheet names indicate the simulation parameters—for example, “N, T by 2”, “N by 10”, etc., where N is the population size and T is the number of generations over which lambda was evolved. Additional labels in the sheet names refer to specific simulation setups: * Regular: simulation started with ancestral host and shifted to malT- host * malT to malT: landscape shifts between two malT- host landscapes * anc to anc: landscape shifts between two ancestral host landscapes * Common genotypes: simulations st...,