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Daily Transfers, Archiving Populations, and Measuring Fitness in the Long-Term Evolution Experiment with Escherichia coli
Published on: August 18, 2023
Parallel evolutionary dynamics of adaptive diversification in Escherichia coli
Matthew D Herron1, Michael Doebeli
1Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
Plos Biology
|February 23, 2013
Summary
Adaptive diversification in Escherichia coli demonstrates predictable evolutionary dynamics. Competition for resources drove parallel genetic changes, leading to distinct ecotypes and supporting frequency-dependent selection as a driver of biodiversity.
Area of Science:
- Evolutionary biology
- Microbial evolution
- Genetics
Background:
- Evolutionary diversification is a key biological question.
- Geographic isolation is a traditional explanation, but sympatric diversification is increasingly recognized.
- Empirical evidence for the genetic basis of sympatric diversification is lacking.
Purpose of the Study:
- To investigate the genetic basis and evolutionary dynamics of adaptive diversification in sympatry.
- To determine the predictability of diversification in similar ecological settings.
- To provide empirical evidence for frequency-dependent selection driving diversification.
Main Methods:
- Three replicate evolution experiments using Escherichia coli.
- Competition for two carbon sources to induce diversification.
- Whole-genome sequencing of evolved ecotypes.
- Analysis of allele frequency changes from a frozen historical record.
Main Results:
- Diversification into two coexisting ecotypes with distinct metabolic adaptations.
- Identification of parallel and unique genetic changes, including mutations in the same genes.
- Evidence of parallel evolutionary dynamics driven by frequency-dependent co-evolution.
- Demonstration of predictable evolutionary trajectories in independent populations.
Conclusions:
- Adaptive diversification can occur predictably in sympatry.
- Frequency-dependent selection and co-evolution play significant roles in diversification.
- Genetic changes underlying adaptive diversification show parallelism across replicate experiments.
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