Figure 2: trans-meQTL structural characteristics.
From: Characterizing the genetic basis of methylome diversity in histologically normal human lung tissue
(a) Circos plot for trans-meQTLs. The outer rim shows the log10 P-values Manhattan plots of trans-meQTL associations. The innermost network depicts spokes between all trans-meQTL SNPs and their target CpG sites. The red spikes show a master regulatory SNP rs12933229 located at 16p11.2 associated with methylation of CpG sites located in CGIs annotated to five genes. (b) Proportion of CpG probes detected with cis-meQTLs and trans-meQTLs across gene regions. The asterisks ‘*, **, ***’ indicate t-test P<0.05, 0.01 and 0.0001, respectively, for the comparison between CGI and non-CGI regions. CGI regions are strongly enriched with trans-meQTLs, while non-CGI regions are enriched with cis-meQTLs. CpG sites in 3′ UTR regions show an opposite trend. (c) The association between a SNP denoted as G and a distal CpG-site B may be mediated through a proximal CpG-site A. (d) For each trans-association (G, B) pair, the dots show their marginal versus partial correlation coefficients upon conditioning on the proximal A CpG probes. Analysis was based on 210 samples. Reduction of correlation coefficients by conditioning on A suggests the magnitude of the mediation effect.
