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Do deleterious mutations act synergistically? Metabolic control theory provides a partial answer
1Laboratory of Mathematical Biology, MRC National Institute for Medical Research, Mill Hill, London, England.
Genetics
|January 1, 1993
Summary
Two deleterious mutations affecting metabolic pathways are synergistic when they impact the same enzyme. The fitness consequences of mutations in different enzymes depend on selection pressures, influencing predictions for prokaryotes and eukaryotes.
Area of Science:
- Biochemistry
- Evolutionary Biology
- Systems Biology
Background:
- Deleterious mutations can impact metabolic pathway dynamics and organismal fitness.
- Understanding the synergistic or antagonistic effects of multiple mutations is crucial for evolutionary and systems biology.
Purpose of the Study:
- To apply Metabolic Control Theory to determine conditions for synergistic effects of two deleterious mutations in metabolic pathways.
- To analyze how different fitness objectives influence the epistasis (gene interaction) between metabolic mutations.
Main Methods:
- Utilized Metabolic Control Theory to model the effects of mutations on metabolic pathways.
- Analyzed four distinct fitness criteria: maximal flux, maximal intermediate concentration, optimal flux, and optimal pool size.
Main Results:
- Mutations reducing the activity of the same enzyme tend to act synergistically.
- Antagonistic epistasis is predicted for maximal flux selection, while synergistic epistasis is more likely for optimal flux or pool size selection.
- Different fitness objectives lead to varied predictions for mutation effects in prokaryotes versus eukaryotes.
Conclusions:
- The interplay between mutation location, fitness objectives, and epistasis shapes the evolutionary impact of metabolic mutations.
- The model's predictions align with observations of mosaic gene structures in bacteria, suggesting clonal populations can accumulate diverse genetic elements.