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Time to fixation in changing environments
1Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
Genetics
|November 5, 2021
Summary
Environmental changes impact natural selection. We studied fixation times for beneficial and deleterious mutations in changing environments, finding recessive deleterious mutations are strongly affected, unlike beneficial ones.
Area of Science:
- Evolutionary biology
- Population genetics
- Theoretical ecology
Background:
- Natural selection studies often assume constant environments, but natural settings fluctuate.
- Understanding evolution in changing environments is crucial for ecological and genetic insights.
Purpose of the Study:
- To investigate how a periodically changing environment affects the conditional fixation time of new mutations.
- To compare fixation times of beneficial and deleterious mutants in dynamic versus static environments.
Main Methods:
- Mathematical modeling of a finite, randomly mating diploid population.
- Analysis of conditional fixation time for mutants with intermediate dominance.
- Comparison of results under slowly varying and static environmental conditions.
Main Results:
- The symmetry in fixation times between beneficial and deleterious mutants (seen in static environments) is broken in changing environments.
- Initially beneficial mutants show fixation times weakly dependent on dominance and close to static environment results.
- Recessive deleterious mutants exhibit significantly altered fixation times in changing environments compared to constant ones.
Conclusions:
- Temporal environmental variation has a mild effect on genetic diversity patterns for beneficial sweeps.
- Environmental fluctuations can strongly influence genetic diversity patterns arising from recessive deleterious sweeps.
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