Effect of select mutations on methylation at the target site and at non-target sites.

(a) frequency of methylation the target CpG site at a gap length of 12 nucleotides from the PAM site. The P values are from Student’s t-tests (n = 5 for the no mutation and n = 2 for Y305F and T313A). Four of the five measurements for no mutation are from [13] and one is new. Comparison of the effect of the (b) Y305F and (c) T313A mutations on the frequency of off-target methylation at 482 C’s in 241 non-target CpG sites on plasmid pReporter. Frequencies were determined by high-throughput bisulfite sequencing.