Fig. 3.

Synthetic mimics of DNA fragments detected in cells undergoing primed adaptation function as prespacers. a Prespacer efficiency assay. Top, introduction of synthetic DNA into cells containing a CRISPR array and plasmid that directs expression of cas1 and cas2. Bottom, integration of synthetic DNA into the CRISPR array occurs in either a direct (Sp^direct) or reverse (Sp^reverse) orientation. b Results. Left, oligonucleotides analyzed. Right, percentage of arrays containing oligo-derived spacers having a direct (light green) or reverse (dark green) orientation (mean ± SEM of three biological replicates). Source data are provided as a Source Data file