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Related Experiment Video

Updated: Mar 11, 2026

Determination of the Mating Efficiency of Haploids in Saccharomyces cerevisiae

Determination of the Mating Efficiency of Haploids in Saccharomyces cerevisiae

Published on: December 2, 2022

Fixation Probability in a Haploid-Diploid Population.

Kazuhiro Bessho¹, Sarah P Otto²

¹JSPS Research Fellow, Department of Evolutionary Studies of Biosystems, School of Advanced Sciences, SOKENDAI (The Graduate University for Advanced Studies), Hayama, 240-0193, Japan bessho_kazuhiro@soken.ac.jp otto@zoology.ubc.ca.

|November 21, 2016

Summary

Organisms with both haploid and diploid stages have different allele fixation probabilities than purely haploid or diploid species. Our models predict these probabilities, aiding evolutionary studies.

Keywords:

Moran model Wright–Fisher model fixation probability haploid-diploid life cycle variance effective population size

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Last Updated: Mar 11, 2026

Determination of the Mating Efficiency of Haploids in Saccharomyces cerevisiae

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Area of Science:

Population Genetics
Evolutionary Biology
Theoretical Biology

Background:

Traditional population genetics models often simplify life cycles to be exclusively haploid or diploid.
Many organisms, including algae and fungi, possess complex life cycles with distinct haploid and diploid phases.
Understanding allele dynamics in these complex life cycles is crucial for evolutionary insights.

Purpose of the Study:

To investigate the probability of fixation for selected alleles in organisms with haploid-diploid life cycles.
To develop and apply genetic models that account for both haploid and diploid population stages.
To compare fixation probabilities in haploid-diploid organisms with those in purely haploid or diploid species.

Main Methods:

Development of a genetic model incorporating haploid-diploid life cycle dynamics.
Application of the Moran and Wright-Fisher population models.
Utilizing branching process and diffusion approximations for calculating fixation probabilities.

Main Results:

Branching process approximation provides accurate fixation probabilities for large populations with beneficial mutations.
Diffusion approximation is effective for small populations and deleterious alleles under weak selection.
Fixation probabilities can differ significantly in haploid-diploid organisms compared to haploid or diploid-only species, especially when one phase dominates.

Conclusions:

Haploid-diploid life cycles introduce unique evolutionary dynamics not captured by simplified models.
The developed approximations offer accurate predictions for allele fixation across various population sizes and selection strengths.
These findings highlight the importance of considering complex life cycles in population genetic theory and evolutionary research.