Epigenetic characteristics within coding regions of varying size. (a) Heatmaps showing the coding-region profiles of nucleosomes (left side) or methylation (right side) averaged over 100 neighboring genes ordered by size. A total of 25,883 genes were used. Each row represents a mean-centered profile for each gene. The average profile of genes of similar size is given on the left side (for nucleosome level) and the right side (for methylation level) of the heatmap. (b) A combined profile of the heatmap signatures of the two marks at each end (marks > 0.5 at the 5' end and > 1 at the 3' end were considered significant). (c) Genome-wide average of nucleosome occupancy in yeast and fly (upper panels) and methylation level in Arabidopsis and rice (lower panels) according to relative positions within the coding region. The median length of coding regions is shown. (d) Size of coding regions from each species. The box width is proportional to the square root of the number of measured genes.