Transient mutation bias increases the predictability of evolution on an empirical genotype-phenotype landscape

Area of Science:

• Evolutionary Biology
• Microbial Genetics

Background:

• Predicting evolutionary trajectories requires understanding selection and mutation bias.
• Mutation bias can influence adaptive paths by favoring specific mutational steps.

Purpose of the Study:

• To investigate if transient mutation bias can predictably guide populations to optimal phenotypes.
• To determine if mutation bias leads to superior or inferior evolutionary outcomes.

Main Methods:

• Utilized a model system of motile mutants derived from non-motile Pseudomonas fluorescens SBW25.
• Empirically elucidated a genotype-phenotype landscape focused on motility.
• Analyzed a specific evolutionary trajectory exhibiting significant mutation bias.

Main Results:

• Transient mutation bias was shown to facilitate rapid and predictable adaptation.
• Populations were guided towards the strongest observed phenotype.
• Mutation bias steered evolution away from equivalent but inferior trajectories.

Conclusions:

• Transient mutation bias can reliably direct evolutionary trajectories towards the most advantageous phenotypes.
• This bias enhances predictability in adaptation by constraining accessible evolutionary paths.
• The findings have implications for understanding and predicting evolutionary processes in various biological systems.