 Anti-CRISPR results from an evolutionary process occurred in phages in order to avoid having their genomes destroyed by the prokaryotic cells that they will infect.Before the discovery of this type of family proteins, the acquisition of mutations was the only way known that phages could use to avoid CRISPR-Cas mediated shattering, by reducing the binding affinity of the phage and CRISPR.Nonetheless, bacteria have mechanisms to retarget the mutant bacteriophage, a process that it is called "priming adaptation".