Random with Respect to Fitness or External Selection? An Important but Often Overlooked Distinction

Area of Science:

• Evolutionary Biology
• Genetics
• Molecular Biology

Background:

• The concept of 'randomness with respect to fitness' is a cornerstone of evolutionary theory.
• Existing experimental frameworks underpin the widely accepted notion that mutations occur randomly relative to their adaptive value.

Purpose of the Study:

• To re-evaluate the definition and experimental basis of 'randomness with respect to fitness' in mutations.
• To distinguish between randomness relative to external selection and randomness relative to fitness.
• To address ongoing debates regarding directed mutation.

Main Methods:

• Analysis of experimental methodologies used to assess mutation randomness.
• Conceptual distinction between mutation randomness concerning external selection versus fitness.
• Review of mathematical, experimental, and inferential frameworks.

Main Results:

• Experiments demonstrating mutation randomness primarily show randomness with respect to current external selection, not necessarily fitness.
• A critical distinction exists between mutations being random relative to selection and random relative to fitness.
• This distinction offers a potential resolution for debates on directed mutations.

Conclusions:

• The established "randomness with respect to fitness" requires re-evaluation based on experimental limitations.
• Differentiating between randomness relative to selection and fitness is crucial for evolutionary and genetic research.
• This conceptual clarification has significant implications for future research and interpretation of mutation data.