Dynamic epistasis under varying environmental perturbations

Area of Science:

• Genetics
• Evolutionary Biology
• Systems Biology

Background:

• Epistasis, the non-independent effects of mutations at different genetic loci, is crucial for understanding genetic and evolutionary processes.
• Current understanding of epistatic dynamics across multiple conditions is limited due to experimental screening challenges.

Purpose of the Study:

• To simulate and analyze genome-wide epistatic landscapes under various environmental perturbations.
• To investigate gene-gene epistatic interactions and their dynamics across different conditions.

Main Methods:

• Utilized flux balance analysis (FBA) to model epistatic interactions.
• Simulated environmental perturbations, including changes from glucose-abundant to nutrient-limiting conditions.

Main Results:

• Epistasis tends to become more positive under nutrient limitation, suggesting reduced selection efficacy.
• Identified a stable core of epistatic interactions present across all conditions.
• Observed condition-specific epistatic interactions forming a scale-free network, distinct from the stable core.
• Genes in the stable network show correlated evolutionary rates, unlike those in condition-specific networks.

Conclusions:

• Environmental perturbations significantly alter epistatic landscapes.
• The study provides a novel, genome-wide perspective on epistatic dynamics and their relationship with environmental variability and gene evolution.