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Following the Dynamics of Structural Variants in Experimentally Evolved Populations
Published on: February 3, 2023
Function-specific accelerations in rates of sequence evolution suggest predictable epistatic responses to reduced
Tobias Warnecke1, Eduardo P C Rocha
1Department of Biology and Biochemistry, University of Bath, Bath, UK. Tobias.Warnecke@crg.es
Molecular Biology and Evolution
|February 26, 2011
Summary
Smaller populations accelerate molecular evolution, especially in bacterial pathogens. Genes buffering slightly deleterious mutations show surprisingly higher rate accelerations, suggesting compensatory evolution.
Area of Science:
- Evolutionary biology
- Molecular evolution
- Genomics
Background:
- Changes in effective population size influence molecular evolution rates.
- Slightly deleterious mutations are more likely to fix in smaller populations, accelerating evolution.
- Previous studies validated this in endosymbionts and island taxa.
Purpose of the Study:
- To investigate evolutionary rate accelerations in bacterial pathogens with reduced effective population sizes.
- To analyze substitution rate dynamics across different gene functional categories in bacterial clades.
- To test the hypothesis that reduced effective population size induces epistatic responses in buffer genes.
Main Methods:
- Comparative genomics analysis of six phylogenetically independent bacterial clades.
- Analysis of substitution rate dynamics across coding sequences.
- Examination of gene functional categories, focusing on chaperone genes.
Main Results:
- Rate accelerations were observed in bacterial pathogens (e.g., Bacillus anthracis, Yersinia pestis).
- Relative coding sequence evolution rates varied by gene functional category.
- Chaperone genes, which buffer against deleterious mutations, showed stronger rate accelerations at both nonsynonymous and synonymous sites.
Conclusions:
- Reduced effective population size predictably accelerates molecular evolution in bacterial pathogens.
- Buffer genes, like chaperones, exhibit unexpectedly higher rate accelerations.
- Elevated substitution rates in buffer genes may result from compensatory substitutions driven by accumulating deleterious mutations genome-wide.
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