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Updated: May 15, 2025
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Determination of the Mating Efficiency of Haploids in Saccharomyces cerevisiae
Published on: December 2, 2022
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Historical effects during experimental evolution of multicellularity in Saccharomyces cerevisiae
Joleen Khey1,2, Michael Travisano2,3,4
1Department of Plant and Microbial Biology, University of Minnesota, St Paul, Minnesota, United States.
Summary
Early evolutionary changes significantly impact future adaptations. This study shows that a population's history, even over hundreds of generations, shapes its adaptive evolution, demonstrating historical contingency in biological systems.
Area of Science:
- Evolutionary biology
- Genetics
- Microbiology
Background:
- Natural selection drives adaptive evolution, but outcomes depend on a population's genetic makeup.
- Prior evolutionary history influences a population's genetic background and thus its adaptive potential.
Purpose of the Study:
- To investigate the scope of historically contingent outcomes in adaptive evolution.
- To examine how past evolutionary events affect subsequent adaptations in yeast populations.
Main Methods:
- Selection experiments with alternating adaptations for size in laboratory yeast populations.
- Utilizing genetic recombination (selfing) to study the regeneration of multicellularity.
- Analyzing cellular architectures of evolved multicellular phenotypes.
Main Results:
- Genetic recombination regenerated multicellularity from previously unicellular genotypes.
- These genotypes rapidly re-evolved multicellularity under new selection pressures.
- Secondarily evolved multicellular phenotypes exhibited varied cellular architectures.
- Earliest adaptive changes had persistent evolutionary consequences, even over hundreds of generations.
Conclusions:
- Adaptive evolution is historically contingent, with early changes having lasting effects.
- The evolutionary history of a lineage significantly constrains or directs future adaptive pathways.
- Historical contingency plays a crucial role in shaping evolutionary trajectories.
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