Imprecise Spacer Acquisition Generates CRISPR-Cas Immune Diversity through Primed Adaptation.Many prokaryotes possess CRISPR-Cas adaptive immune systems to defend against viruses and invading mobile genetic elements.  CRISPR-Cas immunity relies on genetic memories, termed spacers, for sequence-specific recognition of infections.  Type I CRISPR-Cas systems use existing spacers to enhance the acquisition of new spacers through primed CRISPR adaptation (priming).  We propose that slipped spacers provide a route to increase population-level spacer diversity that pre-empts phage escape mutant proliferation and that the trade-off between adaptation and immunity is important in diverse CRISPR-Cas systems.
CRISPR-Cas
Imprecise Spacer Acquisition Generates CRISPR-Cas Immune Diversity through Primed Adaptation.Many prokaryotes possess CRISPR-Cas adaptive immune systems to defend against viruses and invading mobile genetic elements.  CRISPR-Cas immunity relies on genetic memories, termed spacers, for sequence-specific recognition of infections.  Type I CRISPR-Cas systems use existing spacers to enhance the acquisition of new spacers through primed CRISPR adaptation (priming).  We propose that slipped spacers provide a route to increase population-level spacer diversity that pre-empts phage escape mutant proliferation and that the trade-off between adaptation and immunity is important in diverse CRISPR-Cas systems.
CRISPR-Cas