This month in The Journal

Whereas cis-acting regulatory variants are located near their target genes and affect regions such as promoters and enhancers, trans-acting regulatory variants can be located anywhere in the genome and affect expression through a variety of indirect mechanisms. Trans-eQTLs contribute a sizable fraction of gene expression variation, but identifying these variants continues to pose challenges. Indeed, it is thought that mismapping of sequencing reads could lead to spurious results, suggesting the need to revisit the known catalog of trans-eQTLs for mismapping artifacts.