The Impact of Dominance on Adaptation in Changing Environments

Area of Science:

• Evolutionary Biology
• Population Genetics
• Environmental Change

Background:

• Natural environments are dynamic, necessitating an understanding of population adaptation mechanisms.
• The influence of environmental fluctuations on evolutionary trajectories is a key area of research.

Purpose of the Study:

• To investigate how the fixation probability of a rare mutant is affected by its dominance and the rate of environmental change.
• To determine if dominance effects observed in static environments persist in periodically changing conditions.

Main Methods:

• Mathematical modeling of a finite, diploid population.
• Analysis of fixation probability for rare mutants under varying environmental change rates and dominance coefficients.

Main Results:

• In slowly changing environments, dominance effects mirror those in static environments (beneficial/deleterious mutants are more/less likely to fix if dominant).
• In rapidly changing environments, dominance effects diverge, depending on the mutant's initial fitness and time-averaged fitness.
• Recurrent mutations diminish the influence of dominance on evolutionary dynamics.

Conclusions:

• Environmental change rate significantly modulates the impact of dominance on population adaptation.
• In fast-changing environments, selection pressures at the time of mutation appearance and averaged over time determine dominance effects.
• Dominance plays a less critical role in evolutionary dynamics when mutations occur recurrently.