CRISPR/Cas9 technology generated a valine to glycine (V721G; GTT to GGC) and leucine to glycine (L722G; CTG to GGC) substitutions at amino acids 721 and 722, respectively, in the PCD domain. These mutations correspond to the human V729G/L730G mutation that abolishes the PER2-CK1 association. (J:326603)