Global DNA methylation profiles. (A) Global pattern of CpG methylation in the four groups. The methylation levels of all CpGs were calculated and categorized into five color-coded methylation states. CpG coverage (y-axis) shows the proportion of CpGs covered with different methylation levels. (B) The ”pvclust” tree diagram clustering based on methylation of CpGs in the whole genome. (C) Average CpG methylation levels of different genetic regions. Five kilo base regions upstream and downstream of each gene were divided into 100-base pair (bp) intervals. Each coding sequence was divided into 20 intervals (5% per interval).