DNA Methylation of the First Exon Is Tightly Linked to Transcriptional Silencing
Figure 2
Patterns of gene cassette methylation in T cells.
Each gene cassette element was classified as unmethylated (lowest 10% methylation quantile) or methylated (top 90% methylation quantile). The odds ratio (log2 transformed) indicates the likelihood of an element being methylated if the gene body (A), promoter (B), TSS (C), first exon (D), any intron (E), any internal exon (F), last exon (G) or TTS (H) is methylated. Odds ratios, calculated using Fisher's exact test for count data, represent a conditional maximum likelihood estimate quantifying the strength of the correlation between methylation of each gene cassette element. The odds ratio for the autocorrelation of each element is infinite and represented by grey boxes. Representative data is shown for human blood T cells but the pattern is the same in granulocytes and AML cells.