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Does Adaptive Protein Evolution Proceed by Large or Small Steps at the Amino Acid Level?
Juraj Bergman1,2, Adam Eyre-Walker3
1Institut für Populationsgenetik, Vetmeduni Vienna, Wien, Austria.
Molecular Biology and Evolution
|March 24, 2019
Summary
Large and small effect mutations drive protein evolution. This study found that similar amino acid changes are more common in both adaptive and neutral protein evolution across Drosophila species.
Area of Science:
- Evolutionary Biology
- Molecular Evolution
- Genomics
Background:
- Understanding the role of mutation size in adaptation is a key evolutionary question.
- Protein evolution is shaped by both adaptive and neutral processes.
Purpose of the Study:
- To investigate the relative contribution of different-sized mutations to protein adaptation.
- To analyze the rate and type of amino acid substitutions in Drosophila.
Main Methods:
- Utilized a McDonald-Kreitman type approach.
- Analyzed genome-wide data from multiple Drosophila species.
- Estimated rates of adaptive and neutral evolution between amino acid pairs.
Main Results:
- The rate of adaptive evolution is highest for amino acid substitutions between similar amino acids.
- A higher proportion of mutations are adaptive among similar amino acids.
- Neutral evolution rates are also higher between similar amino acids.
Conclusions:
- Protein evolution, both adaptive and nonadaptive, is predominantly driven by substitutions between similar amino acids.
- The findings suggest a significant role for small-effect mutations in protein evolution.
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