Selective Sweep at a QTL in a Randomly Fluctuating Environment.

Area of Science:

• Evolutionary biology
• Population genetics
• Quantitative genetics

Background:

• Adaptation relies on phenotypic traits influenced by selection pressures that vary with the environment.
• Allelic frequency dynamics at quantitative trait loci (QTL) are affected by trait effects, interactions with other loci, and environmental changes.
• Environments often contain random noise, characterized by magnitude and temporal autocorrelation, influencing predictability.

Purpose of the Study:

• To investigate the evolutionary dynamics of a mutation affecting a quantitative trait in an autocorrelated stochastic environment.
• To examine the impact of background polygenic variance and phenotypic plasticity on adaptation.
• To understand how environmental fluctuations affect the probability of a complete sweep at a QTL.

Main Methods:

• Theoretical modeling of mutation dynamics at a quantitative trait locus (QTL).
• Analysis of selection pressures in autocorrelated stochastic environments.
• Incorporation of background polygenic variance and phenotypic plasticity into evolutionary models.

Main Results:

• Stochastic environmental fluctuations increase evolutionary variance, affecting the probability of QTL sweeps.
• Background polygenic variation limits stochastic variance in population genetics at the QTL.
• For plasticity QTL, fluctuations influence selection coefficients, and mutations can be favored by plasticity despite initial mismatches.

Conclusions:

• Background polygenic variation plays a critical role in modulating the effects of environmental stochasticity on adaptation.
• Phenotypic plasticity can be a significant target of selection, even leading to favored mutations that initially mismatch the optimum.
• Understanding these complex interactions is crucial for predicting evolutionary trajectories in changing environments.