Fluctuating environments select for short-term phenotypic variation leading to long-term exploration

Area of Science:

• Evolutionary biology
• Computational biology
• Genetics

Background:

• Genetic spaces are modeled as fitness landscapes or genotype-to-phenotype maps.
• The mutational landscape, comprising genotypes near a given one, dictates short-term evolutionary potential.
• Wider phenotypic diversity in mutational neighborhoods increases evolvability; fewer changes indicate robustness.

Purpose of the Study:

• To investigate how environmental changes affect the distribution of phenotypes available through mutation.
• To determine if changing environments alter subsequent evolutionary dynamics.
• To compare the evolvability of populations in static versus cyclically changing environments.

Main Methods:

• Evolved digital organism populations under static and cyclically changing environments.
• Characterized local genotype-phenotype maps by examining phenotypic diversity from mutations.
• Analyzed evolutionary dynamics in response to environmental shifts.

Main Results:

• Environmental change promotes more evolvable mutational landscapes with diverse phenotypes, while suppressing deleterious mutations.
• Populations in harsh environments exhibit more frequent phenotype switching than those in benign environments.
• Harsh environments lead to population bottlenecks, shorter coalescence times, and increased likelihood of beneficial phenotypic shifts.

Conclusions:

• Environmental dynamism can align short-term adaptation pressures with long-term evolvability.
• Static environments favor immediate optimization over long-term adaptive potential.
• Cyclically changing environments drive populations towards exploring more diverse and potentially productive regions of the genetic space.