Linking temperature dependence in fitness effects of mutations to thermal niche adaptation
Data files
Aug 31, 2023 version files 28.65 KB
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mpee.thermal.niche.adaptation.xlsx
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README.md
Sep 05, 2023 version files 17.35 KB
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Density_data.csv
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Fitness_data.csv
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R_code.txt
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README.md
Abstract
Fitness effects of mutations may generally depend on temperature that influences all rate-limiting biophysical and biochemical processes. Earlier studies suggested that high temperatures may increase the availability of beneficial mutations (“more beneficial mutations”), or allow beneficial mutations to show stronger fitness effects (“stronger beneficial mutation effects”). The “more beneficial mutations” scenario would inevitably be associated with increased proportion of conditionally beneficial mutations at higher temperatures. This in turn predicts that populations in warm environments show faster evolutionary adaptation but suffer fitness loss when faced with cold conditions, and those evolving in cold environments become thermal-niche generalists (“hotter is narrower”). Under the “stronger beneficial mutation effects” scenario, populations evolving in warm environments would show faster adaptation without fitness costs in cold environments, leading to a “hotter is (universally) better” pattern in thermal niche adaptation. We tested predictions of the two competing hypotheses using an experimental evolution study in which populations of two model bacterial species, Escherichia coli and Pseudomonas fluorescens, evolved for 2,400 generations at three experimental temperatures. Results of reciprocal transplant experiments with our P. fluorescens populations were largely consistent with the “hotter is narrower” prediction. Results from the E. coli populations clearly suggested stronger beneficial mutation effects at higher assay temperatures, but failed to detect faster adaptation in populations evolving in warmer experimental environments (presumably because of limitation in the supply of genetic variation). Our results suggest that the influence of temperature on mutational effects may provide insight into the patterns of thermal niche adaptation and population diversification across thermal conditions.
README: Title of Dataset: Linking temperature dependence of fitness effects of mutations to thermal niche adaptation
Description of the data and file structure
There are three data files.
The "Density data" file (cvs table) shows the mean population densities (log-transformed) over time of each evolution line during the selection experiment. Nine incubators were used in this study, randomly assigned into three blocks (A, B and C). The three incubators in each block were set 19, 26 or 31°C. There were two replicate microcosms for each species in every incubator. Variable "block" indicate which block an evolution line belong to; variable "evolution.temperature" indicates at which temperature the evolution lines are selected; variable "replicate" indicates the within-incubator replicate ID. Species "E" represents Escherichia coli and P, Pseudomonas fluorescens. Densities were measured as colony formation units per ml.
The "Fitness data" file (cvs table) gives fitness assayed in home and alternative environments, in a format convenient for paired-t tests. Variable "assay.temnperature" indicates at which temperature fitness was measured. Variable "block" indicate which block an evolution line belong to; variable "evolution.temperature" indicates at which temperature the evolution lines are selected. Variable "replicate" indicates the within-incubator replicate ID. Species "E" represents Escherichia coli and P, Pseudomonas fluorescens. Variable "tag" indicates microcosm label which integrates information about block, evolution temperature and replicate ID. Variable "change.in.fitness" show the relative fitness of each evolved population against its ancetral strain (measured by head-to-head competition).
The "R code" file (txt file) provide code used for data analysis presented in the article associated with the data.
Sharing/Access information
Links to other publicly accessible locations of the data: NA
Data was derived from the following sources: NA