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

Whether and how the spatial arrangement of a population influences adaptive evolution has puzzled evolutionary biologists. Theoretical models make conflicting predictions about the probability a beneficial mutation will become fixed in a population for certain topologies like stars, in which “leaf” populations are connected through a central “hub.” To date, these predictions have not been evaluated under realistic experimental conditions. Here, we test the prediction that topology can change the dynamics of fixation both in vitro and in silico by tracking the frequency of a beneficial mutant under positive selection as it spreads through networks of different topologies. Our results provide empirical support that metapopulation topology can increase the likelihood that a beneficial mutation spreads, broadens the conditions under which this phenomenon is thought to occur, and points the way towards using network topology to amplify the effects of weakly favored mutations under directed e..., This data was collected from experimentally evolving laboratory populations of P. aeruginosa strain 14 (PA14) under a sub-inhibitory concentration of Ciprofloxacin and a novel agent-based SANCTUM model. The raw counts and proportions of the mutant bacteria PA14-gyrA wild-type non-mutant PA14-LacZ are both available. The proportions have been used to perform all the statistical analyses. , , # Experimental evidence that network topology can accelerate the spread of beneficial mutations

## Description of the data and file structure

This dataset was collected from a selection experiment where 4-deme metapopulations of *Pseudomonas aeruginosa* were grown in rich and complex laboratory media supplemented with a subinhibitory concentration of the antibiotic Ciprofloxacin. In one of the demes (Patch 3), a beneficial mutant of *Pseudomonas aeruginosa* that has an advantage for growing in the presence of Ciprofloxacin (PA14-gyrA) was inoculated at a low frequency (1:1000 ratio) along with the wild-type bacteria (PA14-LacZ). All the other patches were inoculated with the wild-type bacteria (PA14-LacZ). In the X-Gal supplemented solid growth media, PA14-LacZ colonies appear blue but PA14-gyrA colonies appear white. The increase in the frequency of the beneficial mutant (PA14-gyrA) in the whole metapopulation was measured by counting blue and white colonies and taking the proportion...