Non-destructive enzymatic deamination enables single molecule long read sequencing for the determination of 5-methylcytosine and 5- hydroxymethylcytosine at single base resolution

Bisulfite treatment damages the DNA leading to fragmentation and loss of long-range methylation information. To overcome this limitation of bisulfite treated DNA we applied a new enzymatic deamination approach, termed EM-seq (Enzymatic Methyl-seq) to long-range sequencing technologies. Our methodology, named LR-EM-seq (Long Range Enzymatic Methyl-seq) preserves the integrity of DNA allowing long-range methylation profiling of 5-mC and 5-hmC) over several kilobases of genomic DNA. Applied to known differentially methylated regions (DMR), LR-EM-seq achieves phasing of over 5 kb resulting in much broader and better defined DMRs than previously reported.