Viktor Mamontov, Alexander Martynov, Natalia Morozova, Konstantin Lukyanov and Konstantin Severinov have co-authored a paper “Persistence of plasmids targeted by CRISPR interference in bacterial populations” that has been recently published in PNAS. Using microbiological, live microscopy and microfluidics analyses the researchers demonstrate that plasmids can persist for multiple generations in some Escherichia coli cell lineages at conditions of continuous targeting by the type I-E CRISPR-Cas system. They used mathematical modeling to show how plasmid persistence in a subpopulation of cells mounting CRISPR interference is achieved due to the stochastic nature of CRISPR interference and plasmid replication events. The scientists propose that in nature, the observed diversification of phenotypes may allow rapid changes in the population structure to meet the demands of the environment. Full text of the paper is available here.