Evolutionary rescue by compensatory mutations is constrained by genomic and environmental backgrounds

Area of Science:

• Evolutionary biology
• Genetics
• Systems biology

Background:

• Deleterious mutations can be overcome by secondary mutations during evolution.
• Compensatory evolution may reveal genetic solutions applicable as therapeutic targets.
• The universality of these solutions across different genetic and environmental contexts is unknown.

Purpose of the Study:

• To test if compensatory evolution yields universal genetic solutions for therapeutic targets.
• To investigate the influence of genetic background and environment on evolutionary rescue outcomes.
• To identify context-specific molecular mechanisms and genetic targets for therapeutic intervention.

Main Methods:

• Experimental evolution was used to study rescue in a yeast model of Wiskott-Aldrich syndrome.
• Two distinct genetic backgrounds and two different carbon sources were employed.
• Analysis focused on mutation rates, types, molecular mechanisms, genetic targets, and fitness costs.

Main Results:

• Evolutionary rescue outcomes were significantly influenced by genotype, environment, or their interaction.
• Compensatory mutation rates, types, and molecular mechanisms varied across experimental conditions.
• Specific genetic targets and associated fitness costs differed depending on the context.
• Biologically favored therapeutic targets for Wiskott-Aldrich syndrome were identified, including one targeted by an existing drug.

Conclusions:

• The trajectory of compensatory evolution is highly contingent on initial conditions (genotype and environment).
• Epistasis and environmental constraints critically shape adaptive landscapes and evolutionary rates.
• Findings highlight the need for context-specific approaches in developing therapies based on compensatory evolution.