The evolutionary advantage of heritable phenotypic heterogeneity

Area of Science:

• Evolutionary biology
• Genetics
• Population dynamics

Background:

• Phenotypic plasticity is a key evolutionary mechanism.
• It influences adaptive immunity, cancer development, and pathogen drug resistance.
• Understanding the evolutionary advantage of plastic alleles is crucial.

Purpose of the Study:

• To investigate the evolutionary fate of a new mutation conferring phenotypic plasticity.
• To analyze the fixation probability of plastic alleles in finite populations.
• To determine how phenotypic memory, environmental changes, and population size affect this probability.

Main Methods:

• Mathematical modeling of allele fixation in a finite population.
• Analysis of fixation probability as a function of phenotypic memory, phenotype variance, environmental change rate, and population size.
• Comparison with infinite-population models.

Main Results:

• The advantage of phenotypic plasticity is highly dependent on the environmental regime.
• In constant environments, plasticity is advantageous, with fixation probability increasing with phenotypic memory.
• In fluctuating environments, an optimal phenotypic memory maximizes fixation probability and geometric mean fitness.

Conclusions:

• Phenotypic plasticity's evolutionary success is contingent on environmental stability and heritability.
• Optimal phenotypic memory balances adaptation and stability in fluctuating environments.
• Findings have implications for designing therapies against persistent pathogens and drug resistance.