Deaminase is attached by a linker to nuclease-deficient CRISPR/Cas9. Guide RNA recognizes the DNA sequence of target genome and the deaminase modifies the base of the unwound DNA.
The figure analyzes the frequency at which mutation was induced in 40 bases of the target DNA sequence. In the nuclease model (left) mainly insertion and deletion are induced but in the deaminase model only point mutation is induced.