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Mutation-biased adaptation in a protein NK model.
1Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Gaithersburg, Maryland, USA. arlin.stoltzfus@nist.gov
Molecular Biology and Evolution
|July 22, 2006
Summary
Mutation bias can drive adaptive evolution, even without neutral evolution. Simulations show a GC:AT bias can persistently alter amino acid composition during adaptive walks.
Area of Science:
- Evolutionary biology
- Molecular evolution
- Genomics
Background:
- Systematic differences in genome and proteome composition are often explained by mutation bias within neutral evolution or by selection.
- A potential driver, mutation-imposed directional bias on adaptation, has been largely overlooked in major evolutionary theories.
Purpose of the Study:
- To investigate the impact of GC:AT mutation bias on adaptive evolution using computational simulations.
- To explore whether mutation bias can influence amino acid composition independently of neutral evolution.
Main Methods:
- Simulations of adaptive walks on an abstract protein fitness landscape (NK model).
- Incorporation of a realistic GC:AT mutation bias into the simulation parameters.
- Analysis of changes in amino acid composition during simulated adaptation.
Main Results:
- A modest GC:AT mutation bias can significantly direct the trajectory of adaptation.
- This bias leads to substantial and persistent alterations in amino acid composition.
- The effect is observed even in the complete absence of neutral evolution.
Conclusions:
- Mutation bias can be a potent force in shaping evolutionary trajectories and genome composition.
- Evolutionary explanations for observed patterns do not solely rely on neutral evolution.
- This study highlights the underappreciated role of mutation bias in driving adaptation.