Genome-wide CRISPRi essentiality mapping in phages λ and P1 identifies sites for DNA barcoding

Researchers at the University of California, Berkeley developed a CRISPR interference method to map gene essentiality in phages and applied it to the coliphages λ and P1, largely recapitulating the known essential genes of λ and giving new insights into P1. They also inserted DNA barcodes into newly identified inessential regions to enable identification, quantification and tracking of phages, and caution that CRISPRi polarity can cause false-positive essentiality calls.