Universal bacterial clade dynamics dominate under predation despite altered phenotypes and mutation targets

Area of Science:

• Evolutionary biology
• Microbial ecology
• Genomics

Background:

• Bacterial evolution is complex, even in stable environments, with emerging and coexisting clades.
• Predator-prey dynamics significantly influence prey evolution, driving defense mechanisms and frequency-dependent selection.

Purpose of the Study:

• To investigate genome-wide evolutionary changes in bacterial prey under long-term ciliate predation.
• To determine if predation alters the patterns of clonal dynamics and adaptation in bacterial populations.

Main Methods:

• Evolved five bacterial prey species under ciliate predation over an extended period.
• Analyzed genome-wide mutations and phenotypic changes in prey populations.
• Compared evolutionary dynamics between predation and control groups.

Main Results:

• Detected clear signals of prey adaptation and changes in genomic mutation targets due to predation.
• Observed that despite increased variant counts, temporal clade dynamics in prey under predation mirrored those of bacteria evolving without predators.
• Found constant emergence, competition, and quasi-stable coexistence of clades in both experimental conditions.

Conclusions:

• Predation imposes selection for defense but does not fundamentally alter the overall patterns of bacterial clade dynamics.
• The genome-wide evolution of bacterial prey under predation is more complex and less predictable than current coevolutionary theories suggest.