Damage introduced by 5mC deamination is influenced by genetic and epigenetic features. (A) Observed relative mutation rates (RMRs) at different genomic features in whole genome sequencing from WEHI-AML-1 and WEHI-AML-2, calculated per Mb of CG dinucleotides (CG corrected), or corrected for methylation status in normal CD34⁺ cells (5mC corrected). (B) Abundance and methylation status for NCG trimers from whole genome bisulfite sequencing derived from normal CD34⁺ cells.³⁷  An RMR value was calculated for WEHI-AML-1 and WEHI-AML-2 for each NCG trimer, accounting for differences in abundance and 5mC status in normal CD34⁺ cells and scaled to account for total mutation load (see supplemental Methods). Individual values are plotted (n = 2), and bars show the mean. (C) RMR values were calculated from exome data for the 5 MBD4-deficient cancers. There was a significant enrichment of mutations in the ACG context compared with TCG (P = .0079, Mann-Whitney U test). (D) RMR values were calculated from whole genome sequencing data generated from Mbd4 knockout (Mbd4-KO) murine blood cell progenitors at 4 months of age. Values from individual colonies are plotted (n = 3), and the bar shows the mean. There was a significant enrichment of mutations in the ACG context compared with TCG (P = .019, Welch’s t test). (E) RMR values were calculated for NCGN tetramers in WEHI-AML-1 and WEHI-AML-2, then separated by replication timing (n = 2).