Figure 4

SMRT-BS validation. (A) Methylation quantitation by SMRT-BS of 42 CpG sites was compared to available data on the same sample using the HumanMethylation450 BeadChip (450K Array), resulting in an overall correlation of 0.906 ± 0.052. Correlation analyses were stratified by amplicon lengths, indicating a reduction in correlation with longer amplicons and possible PCR bias towards unmethylated DNA for the intermediate methylation region (see Results and discussion). (B) Methylation quantitation by SMRT-BS of 174 CpG sites was compared to available data on the same sample using the SureSelect™ Human Methyl-Seq target enrichment next generation sequencing platform (MethylSeq), resulting in an overall correlation of 0.933 ± 0.031. Correlation analyses were stratified by amplicon lengths, indicating a reduction in correlation with longer amplicons and possible PCR bias towards unmethylated DNA for the intermediate methylation region (see Results and discussion).