Average methylation levels of different genomic regions of the three life stages of T. spiralis. (a, b) Average density of methylation levels (a) and percentage of methylation levels (b) (y-axis; Materials and methods) at different functional regions (x-axis). (c, d) Average density of methylation levels (c) or percentage of methylation levels (d) (y-axis) of intervals around genic regions (x-axis). Two-kilobase regions upstream and downstream of each gene were divided into 100-bp (bp) intervals. Each coding sequence or intron was divided into 20 intervals (5% per interval).