DOI: 10.5061/dryad.n9r96
title: Data from: Genetic drift and selection in many-allele range expansions

description: We experimentally and numerically investigate the evolutionary dynamics of
 four competing strains of E. coli with differing expansion velocities in
 radially expanding colonies. We compare experimental measurements of the
 average fraction, correlation functions between strains, and the relative
 rates of genetic domain wall annihilations and coalescences to simulations
 modeling the population as a one-dimensional ring of annihilating and
 coalescing random walkers with deterministic biases due to selection. The
 simulations reveal that the evolutionary dynamics can be collapsed onto
 master curves governed by three essential parameters: (1) an expansion
 length beyond which selection dominates over genetic drift; (2) a
 characteristic angular correlation describing the size of genetic domains;
 and (3) a dimensionless constant quantifying the interplay between a
 colony’s curvature at the frontier and its selection length scale. We
 measure these parameters with a new technique that precisely measures
 small selective differences between spatially competing strains and show
 that our simulations accurately predict the dynamics without additional
 fitting. Our results suggest that the random walk model can act as a
 useful predictive tool for describing the evolutionary dynamics of range
 expansions composed of an arbitrary number of genotypes with different
 fitnesses.
description: Two Strains: eCFP vs.
 eYFP inoculated in equal fractionseCFP and eYFP inoculated
 in equal fractions. Imaged on the 8th day of growth. See the README for
 more info.q2_eCFP_eYFP.zipThree Strains: eCFP, eYFP, and black inoculated in equal fractionseCFP, eYFP, and black inoculated in equal fractions. Imaged on the 8th day of growth. See the README for more info.q3_eCFP_eYFP_black.zipTwo Strains: black vs. mCherry inoculated in equal fractionsblack and mCherry inoculated in equal fractions. Imaged on the 8th day of growth. See the README for more info.q2_black_mCherry.zipThree Strains: eCFP, eYFP, and mCherry inoculated in equal fractionseCFP, eYFP, and mCherry inoculated in equal fractions. Imaged on the 8th day of growth. See the README for more info.q3_eCFP_eYFP_mCherry.zipFour Strains: eCFP, eYFP, black, and mCherry inoculated in equal fractionseCFP, eYFP, black, and mCherry inoculated in equal fractions. Imaged on the 8th day of growth. See the README for more info.q4_eCFP_eYFP_black_mCherry.zipThree Strains: 10% eCFP, 10% eYFP, and 80% mCherryeCFP, eYFP, and mCherry inoculated in fractions of 10%, 10%, and 80% respectively. Imaged on the 8th day of growth. See the README for more info.q3_10percent_eCFP_eYFP_80percent_mCherry.zipWell-mixed fitness of each strain: FACS measurementsSee the "Comparing well-mixed fitness to fitness from expansion velocities" section of our paper. The attached excel file contains the abundance of each strain competing against mCherry (BW003) in well-mixed culture vs. time; we obtained this data from a FACS machine. We used this data to determine the selective advantage of every strain relative to mCherry in well-mixed culture.well_mixed_competition_FACS_data.xlsCalculating the Wall Velocity: Single Sectors of each Strain Sweeping through mCherrySee the "Measuring the domain wall velocities v_w^{ij}" section of our paper. We inoculated 10% of a more fit strain (eCFP, eYFP, or black) and 90% of mCherry so that single sectors of the more fit strain would sweep through mCherry (i.e. we wanted to avoid the collision of domain walls). We used the data contained in this package to calculate the wall velocity v_w^{iR} of each strain sweeping through mCherry. See the attached README for more info.single_sectors_sweeping_through_mcherry.zipIndependent Radial Expansion Velocities of Each StrainSee the "Measuring radial expansion velocities u_i" section of our paper. This dataset contains radius vs. time data of single-strain colonies (one colony per plate) growing on two two separate batches of agar plates. We used this data to determine the average radial expansion velocity of each strain. The third and final batch of plates used to calculate the average radial expansion velocity is in the "Multiple Strains per Plate" repository (it was a control for that experiment, so we included it there). See the README for more information.independent_radial_expansion_velocities_of_each_strain.zipMultiple Strains per Plate: testing if independent radial expansion velocity can predict wall velocitySee Appendix S2. Contains data used to argue that even when controlling for colony expansion velocity's plate-to-plate variability, the wall velocity of one strain sweeping through another is vastly overestimated by standard "geometric optics" predictions. The data in this repository was used to generate all Figures and Tables in Appendix S2. See the README for additional information.multiple_strains_per_plate_radial_expansion_velocities_and_wall_velocities.zip