types [12], [13]. CpG sites that are within CpG Islands [14], [15] were predominately unmethylated. Grouping of mRNAs into high through low expression groups revealed abundance profiles similar to those previously reported (Figure 1D). We next compared CpG methylation and mRNA expression levels at individual loci directly between each possible pair of tissue regions (Figure 1C and 1D, scatterplots). In general levels of DNA methylation and expression were quite similar between tissues. Measures within frontal and temporal cortices were consistently the most alike and cerebellar tissue provided the most distinct profile of the four regions.
