Figure 6: Targets and regulatory correlates of DNA methylation in Z. nevadensis.
From: Molecular traces of alternative social organization in a termite genome
(a) Distributions of CpG o/e for different genomic elements reveals substantial CpG depletion, and thus higher DNA methylation, in introns and exons relative to the genomic background (‘genome’, 1 kb windows) and the region 2 kb upstream of the translation start site (TSS) (‘Promoter’). Inset depicts comparable distributions of GpC o/e, which control for effects unrelated to DNA methylation, such as GC content. (b) Positional CpG o/e of exons and introns in Z. nevadensis and A. mellifera relative to the first eight exons and introns in 5′–3′ orientation from the TSS. (Range in n for element: Z. nevadensis 4,349–12,140; A. mellifera 2,202–7,756.) (c) In Z. nevadensis, an increasing number of alternative splice events co-occurs with decreasing CpG o/e, suggesting that alternatively spliced genes are preferentially targeted by DNA methylation (P<2.2 × 10−16, the Kruskal–Wallis test, n=2,366 for ‘none’ and 904 for each decile 1–10). Means and 95% confidence intervals are plotted in b and c.
