Chunk #1 — Results — Methylation quantitative trait loci (mQTL) in the developing human brain are widespread and predominantly characterized by cis effects
The majority of fetal brain mQTLs (96.3%) involve SNPs and DNA methylation sites on the same chromosome (Fig. 1a and Supplementary Table 2). We defined significant SNP-methylation relationships spanning <500kb as “cis-mQTLs” (n = 15,942, 94.8% of total), with those spanning >500kb or characterized by inter-chromosomal effects (n = 867, 5.16% of total) as representing trans-mQTLs. The strong enrichment of cis-mQTLs concurs with data from other tissues and cell-types7,15–18. Amongst the cis-mQTLs, both effect size (i.e. DNA methylation change per allele, Fig. 1b) and significance (i.e. P-value, Supplementary Fig. 3) are related to the distance between the Illumina 450K array probe and mQTL SNP.
