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Published on: May 19, 2019
Evaluating the impact of population bottlenecks in experimental evolution
Lindi M Wahl1, Philip J Gerrish, Ivan Saika-Voivod
1Applied Mathematics, University of Western Ontario, London, Canada. lwahl@uwo.ca
Genetics
|October 26, 2002
Summary
Experimental evolution bottlenecks reduce beneficial mutation fixation. An optimal dilution ratio of 0.1-0.2 minimizes the loss of beneficial mutations during serial transfers.
Area of Science:
- Evolutionary biology
- Microbial evolution
- Population genetics
Background:
- Experimental evolution frequently uses serial transfers, creating population size bottlenecks.
- These bottlenecks can significantly reduce the probability of beneficial mutations reaching fixation, impacting evolutionary outcomes.
Purpose of the Study:
- To quantify the impact of population bottlenecks on evolutionary dynamics.
- To determine the optimal dilution ratio that maximizes the survival of beneficial mutations.
Main Methods:
- Mathematical modeling of evolutionary dynamics under different growth conditions (exponential vs. resource-limited).
- Analysis of mutation occurrence rates during the growth phase.
- Estimation of mutation loss fractions due to bottlenecks.
Main Results:
- Mutations are equally likely to occur at any time during the growth phase, regardless of growth conditions.
- A dilution ratio between 0.1 and 0.2 is found to minimize the loss of beneficial mutations.
- Severe dilution ratios commonly used in literature increase the loss of rare beneficial mutations.
Conclusions:
- Bottleneck severity in experimental evolution critically influences evolutionary trajectories.
- The derived optimal dilution ratio provides a guideline for designing more effective experimental evolution protocols.
- Understanding bottleneck effects is crucial for accurately interpreting evolutionary dynamics in laboratory settings.
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