DOI: 10.5061/dryad.53k345s
title: Data from: De novo origins of multicellularity in response to predation

description: The transition from unicellular to multicellular life was one of a few
 major events in the history of life that created new opportunities for
 more complex biological systems to evolve. Predation is hypothesized as
 one selective pressure that may have driven the evolution of
 multicellularity. Here we show that de novo origins of simple
 multicellularity can evolve in response to predation. We subjected
 outcrossed populations of the unicellular green alga Chlamydomonas
 reinhardtii to selection by the filter-feeding predator Paramecium
 tetraurelia. Two of five experimental populations evolved multicellular
 structures not observed in unselected control populations within ~750
 asexual generations. Considerable variation exists in the evolved
 multicellular life cycles, with both cell number and propagule size
 varying among isolates. Survival assays show that evolved multicellular
 traits provide effective protection against predation. These results
 support the hypothesis that selection imposed by predators may have played
 a role in some origins of multicellularity.
description: Figure
 3The
 script "Figure3.R" compiles Figure 3. It runs in R version 3.5.1
 and requires the following R libraries: dplyr, reshape2, tools, ggplot2.
 The data for Figure 3 are contained in the folder "Figure3Data".
 Files in this folder are plain-text, comma-separated. The naming
 convention is "strain replicate", so "B2.01 01b"
 contains data for strain B2-01, replicate 01b. Columns in these files are
 as follows: ROI: Region of Interest ROI Number: The individual ROI,
 selected from the image based on thresholding. This typically is a single
 cellular cluster. Mean: Mean 8-bit brightness value for pixels within the
 ROI Min: Minimum 8-bit brightness value for pixels within the ROI Max:
 Maximum 8-bit brightness value for pixels within the ROI IntDen: The
 product of the area of the ROI and its mean 8-bit brightness value
 RawIntDen: The sum of the brightness values for all pixels in the
 ROIFigure3.RFigure 3 DataCompressed archive of data files for Figure 3.Figure3Data.zipFigure 4The script "Figure4.R" compiles Figure 4. It runs in R version 3.5.1 and requires the following R libraries: dplyr, reshape2, ggplot2. The data for Figure 4 are contained in the plain-text, comma-separated file "Figure4Data.csv".Figure4.RFigure 4 DataData for Figure 4. Columns in this file are as follows: Strain: Strain identifier TechRep: Technical replicate ClusterID: Unique, arbitrary identifier per cluster Num.Cells.Progeny: The number of cells observed in a propagule after splitting from parent cluster Num.Cell.Parent: The number of cells observed in the parent cluster after releasing a propagule (determined at same time-step as Num.Cells.Progeny) RepTime.sec: The time at which reproduction (propagule splitting from parent cluster) occurred in the time-lapse. Initially this was reported in time-step, which was then converted to seconds. EntersField.sec: Time at which the cluster entered the field of viewFigure4Data.csvFigure 5 DataData for Figure 5 are contained in the file "Figure5Data.csv". The file format is plain-text, comma-separated. Columns in this file are as follows: Strain: Strain idenitifier nopred1: Absorbance reading for technical replicate 1, predator absent nopred2: Absorbance reading for technical replicate 2, predator absent nopred3: Absorbance reading for technical replicate 3, predator absent nopred4: Absorbance reading for technical replicate 4, predator absent pred1: Absorbance reading for technical replicate 1, predator present pred2: Absorbance reading for technical replicate 2, predator present pred3: Absorbance reading for technical replicate 3, predator present pred4: Absorbance reading for technical replicate 4, predator present Time(h): Number of hours post-inoculation at which the absorbance readings were made MeanDiff: Mean difference between predator absent replicates and predator present replicatesFigure5Data.csv