Paper: “Selection, chance and history in experimental evolutionary reversals to unicellularity”

Author: Maria Rebolleda-Gomez (

Last updates: November 10th 2018


Data of UV resistance and size changes over time.

  • FreqUnisAll.csv : Size measurements for individual clusters of each of the populations and treatments over time.
    • Treatment: UV treatment with notation for ancestral. “A”:ancestral; “N”: No UV; “U”:16 seconds of UV.
    • Population: Ancestral population 1-5 (categorical)
    • Time: Number of transfers (days) n the evolution experiment
    • Area: Area of each multicellular cluster in \(\mu m^2\) as measured with the FlowCam (Fluid imaging technologies, Inc.)
    • Replicate: Replicate line (A, B and C). Three replicate tubes started from each of the ancestral populations.
    • Treatment.1: UV treatment without ancestral category. “N”: No UV; “UV”
  • KillCurve_UV.csv: UV survival data
    • Strain: Name of strain, for multicellular ones the first number identifies the ancestral population and the second one each isolate (see Ratcliff et al., 2012 and Rebolleda-Gomez et al., 2012 for details on these populations and isolation methods).
    • Type: Multicellular (M) or Unicellular (U)
    • CellDens: Density of cells- number of colonies on plate*dilution factor
    • Replicate: Number of replicate (1-3). Order does not matter.
    • WeightedSizeAvg: Volume weighted by precentage of biomass in a given size class.


R code for the analyses in the paper. * KillCurve.R: R code to plot UV survival curves and fit exponential decay model.

  • HistoryChanceSelection.R: R code to calculate the relative contributions of history, chance and selection.

  • ReversalRateGraphs.R: Summarize and plot data. Fit different linear models and check assumptions.