Genome-wide meQTL mapping in cattle blood identifies cis and trans regulators of DNA methylation

A preprint posted to bioRxiv reports the first large-scale methylation quantitative trait locus (meQTL) mapping study in cattle, using a recently developed epigenotyping array called EpiChip. Developed as part of the European RUMIGEN project, EpiChip interrogates 43,317 CpG sites distributed across the bovine genome. The authors applied this resource to blood samples, identifying both cis-acting meQTLs — where a genetic variant influences methylation at a nearby genomic position — and trans-acting meQTLs, where a variant influences methylation at a more distant locus.

MeQTL mapping is of interest in livestock genetics because DNA methylation represents one mechanism through which genetic variation can influence gene expression and ultimately phenotypic traits such as milk production, disease resistance, and growth. The identification of trans-acting meQTLs is particularly informative for understanding how individual genetic variants may propagate regulatory effects across the genome.

The study contributes to a broader effort to build multi-omic reference resources for cattle, analogous to projects such as GTEx in humans, which map how genetic variation shapes molecular phenotypes. The EpiChip array's relatively compact size compared with whole-genome bisulphite sequencing makes large-scale population studies of this kind tractable. The preprint has not yet been peer-reviewed.