Non-genetic adaptation by collective migration.

Area of Science:

• Microbiology
• Evolutionary Biology
• Systems Biology

Background:

• Cell populations adapt to environmental changes through gene regulation, phenotypic switching, or mutations.
• Existing adaptation mechanisms are often limited in the number of traits they can adjust or are slow to develop.

Purpose of the Study:

• To investigate how migrating bacterial populations regulate their phenotypic distribution to adapt to diverse environments.
• To identify novel, rapid, and multi-trait adaptation mechanisms beyond gene regulation and mutation.

Main Methods:

• Generated isogenic Escherichia coli populations with varied swimming behaviors.
• Observed phenotype distributions during migration in liquid and porous environments.
• Measured chemoreceptor abundance distributions during chemotaxis.

Main Results:

• Migrating populations rapidly enriched with high-performing swimming phenotypes, adapting without gene regulation or mutations.
• Adaptation was dynamic and reversible, occurring within a few cell doubling times.
• Migration adapted multiple chemotaxis-related traits simultaneously, driven by a balance between growth-generated diversity and elimination of under-performing phenotypes.

Conclusions:

• Collective migration provides a rapid, flexible, and non-genetic mechanism for cell populations to adapt their phenotypic composition to diverse environments.
• This mechanism, balancing diversity generation and phenotype selection, may be a universal adaptation strategy in various biological contexts, including microbial communities, cancer, and development.