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Updated: Dec 22, 2025
10:52
Precise Phage Mutagenesis with NgTET-Assisted CRISPR-Cas Systems
Published on: October 14, 2025
493
Diversity in CRISPR-based immunity protects susceptible genotypes by restricting phage spread and evolution
Jack Common1, David Walker-Sünderhauf2, Stineke van Houte1
1ESI and CEC, Biosciences, University of Exeter, Penryn, UK.
Journal of Evolutionary Biology
|May 9, 2020
Summary
Increased bacterial CRISPR immunity diversity limits phage spread and evolution. This ecological dilution effect impacts phage population dynamics and the evolution of new phage genotypes.
Area of Science:
- Microbiology
- Evolutionary Biology
- Ecology
Background:
- Host resistance diversity often correlates with reduced pathogen transmission.
- Bacterial CRISPR-Cas adaptive immunity and phage interactions are key in microbial ecosystems.
- Genetic diversity in bacterial immune systems can impede phage adaptation and resistance overcoming.
Purpose of the Study:
- To investigate how CRISPR diversity influences phage spread when resistance can be overcome.
- To determine the effect of immune diversity on phage evolution for broader host range.
- To explore feedback mechanisms between CRISPR diversity, phage spread, and phage evolution.
Main Methods:
- Engineered a host-pathogen system with specific bacterial (CRISPR-Cas) and phage (lytic) genotypes.
- Each bacterial genotype was susceptible to only one phage genotype.
- Analyzed the impact of varying CRISPR diversity on phage spread and evolution.
Main Results:
- Enhanced CRISPR diversity in bacteria conferred a "dilution effect," significantly limiting phage transmission.
- Increased bacterial immune diversity constrained the evolution of phages with broader host ranges.
- Observed feedback where ecological effects of CRISPR diversity influenced phage evolutionary trajectories.
Conclusions:
- Bacterial CRISPR diversity acts as an ecological factor limiting pathogen spread.
- This ecological limitation influences the evolutionary pathways of phages.
- Feedback loops exist between the ecological impact of CRISPR diversity and phage population dynamics and evolution.
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