DNA methylation (DNAm) plays a central role in gene regulation. It helps to define how cells respond to environmental signals and, ultimately, contributes to health or susceptibility to disease. DNAm variation is influenced by genetic, molecular and environmental and other factors. However, the amount and the effects of differences in DNAm from one person to another is poorly understood.

A powerful avenue into researching the functional consequences of changes in DNAm levels is to correlate DNA sequence variants such as single nucleotide polymorphism (SNPs) to DNAm levels to find both local and distal (for example on other chromosomes) effects. Having completed the largest genetic study of DNAm worldwide to date (through the Genetics of DNA Methylation Consortium) by scanning 10 million SNPs genomewide, we have identified 270k SNP-DNAm associations. This was achieved by analysing about 400,000 DNAm sites in blood, which is only 2% of 28 million DNAm sites across the genome. There is a huge potential for improved understanding of DNAm variation between individuals and its influence on health and disease by studying other regulatory regions of the genome using EPIC arrays and by comparing different ethnicities. We propose to systematically map genetic influences on DNAm and to compare these genetic influences across ancestries.