Polymorphisms in cyclically-varying environments

Area of Science:

• Population genetics
• Evolutionary biology

Background:

• Cyclically-varying environments present unique challenges for genetic systems.
• Understanding how gene frequencies evolve under fluctuating selection is crucial for evolutionary studies.

Purpose of the Study:

• To analyze two-allele models in cyclically-varying environments with varying degrees of dominance.
• To compare outcomes between continuous and discrete models of environmental change.

Main Methods:

• Analysis of continuous two-allele models.
• Second-order calculations for discrete two-allele models with arbitrary dominance.
• Investigation of gene frequency dynamics under environmental oscillations.

Main Results:

• In continuous models, gene frequency consistently fluctuates with the environmental cycle.
• Discrete models can lead to either fixation (loss of an allele) or polymorphism (maintenance of multiple alleles).
• The outcome in discrete models depends on the degree of dominance and initial gene frequency.

Conclusions:

• Environmental cyclicity impacts gene frequency dynamics differently in continuous versus discrete models.
• Discrete models offer more complex evolutionary outcomes, including fixation and polymorphism, influenced by dominance and initial conditions.
• These findings contribute to understanding adaptation and genetic diversity maintenance in fluctuating environments.