The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Type II system is currently the most commonly used RNA-Guided Endonuclease technology for genome engineering. There are two distinct components to this system: (1) a guide RNA and (2) an endonuclease, in this case the CRISPR associated (Cas) nuclease, Cas9. The gRNA/Cas9 complex is recruited to the target sequence by the base-pairing between the gRNA sequence and the complement to the target sequence in the genomic DNA. For successful binding of Cas9, the genomic target sequence must also contain the correct Protospacer Adjacent Motiff (PAM) sequence immediately following the target sequence.