Cancer-related loci distinguish tissues due to significant differential methylation. (A) Unsupervised hierarchical cluster and heatmap of methylation levels at a limited set of cancer-loci previously investigated in placental tissue by Chui et al.. The cluster tree indicates the relatedness of the three tissues (x-axis) or the methylation levels (y-axis). The heatmap uses a color scale to indicate the relative methylation level at each locus. Each row of colored lines (N = 117) represents the methylation level for each CpG locus: red for hypomethylated and yellow for hypermethylated (see legend). Each column (n = 13) corresponds to each tissue. (B) Relative locations of RASSF1 methylation. Top panel shows the methylation levels (y-axis) in placenta (orange squares) and fetal (blue crosses) tissues at several loci annotated in or near the RASSF1 locus. Shown below are the relative CpG coverage (vertical black lines) and CpG island location (green rectangle). Bottom panel depicts a partial gene schematic of RASSF1, indicating the relative location of the RASSF1 transcription start site (TSS) and exon 1. The genomic position shown below is relative to HG-19 coordinates.