Genomic mutation rates that neutralize adaptive evolution and natural selection

Area of Science:

• Evolutionary biology
• Population genetics
• Theoretical biology

Background:

• Natural selection drives adaptation by favoring beneficial mutations.
• Mutation rate is a critical factor influencing evolutionary trajectories.
• Excessive mutation can introduce deleterious mutations, potentially counteracting selection.

Purpose of the Study:

• To mathematically define the mutation rates at which adaptive evolution or natural selection becomes neutralized.
• To analyze the impact of varying mutation rates on evolutionary outcomes in asexual populations.
• To provide simple expressions for identifying critical mutation rate thresholds.

Main Methods:

• Application of a standard mathematical model for asexual adaptive evolution.
• Derivation of expressions to delineate mutation rates causing neutralization of selection or adaptation.
• Analysis of theoretical conditions for evolutionary stasis or decline due to high mutation.

Main Results:

• Identified specific mutation rate thresholds where adaptive evolution can be neutralized.
• Demonstrated conditions where natural selection is overwhelmed by deleterious mutations.
• Derived simple mathematical expressions, independent of organism-specific parameters, for these thresholds.

Conclusions:

• Mutation rates critically influence the efficacy of natural selection and the rate of adaptation.
• Extremely high mutation rates can lead to a breakdown of adaptive evolution.
• The derived expressions offer a general framework for understanding mutation-driven evolutionary limits.