Genetic Basis of Alternative Polyadenylation is an Emerging Molecular Phenotype for Human Traits and Diseases

SUMMARY Genome-wide association studies have identified thousands of non-coding variants that are statistically associated with human traits and diseases. However, functional interpretation of these variants remains a major challenge. Here, we describe the first atlas of human 3’ -UTR alternative polyadenylation (APA) Q uantitative T rait L oci (3’QTLs), i.e. ∼0.4 million genetic variants associated with APA of target genes across 46 Genotype-Tissue Expression (GTEx) tissues from 467 individuals. APA occurs in approximately 70% of human genes and substantively impacts cellular proliferation, differentiation and tumorigenesis. Mechanistically, 3’QTLs could alter polyA motifs and RNA-binding protein binding sites, leading to thousands of APA changes. Importantly, 3’QTLs can be used to interpret ∼16.1% of trait-associated variants and are largely distinct from other QTLs such as eQTLs. The genetic basis of APA (3’QTLs) thus represent a novel molecular phenotype to explain a large fraction of non-coding variants and to provide new insights into complex traits and disease etiologies. Highlights The first atlas of human 3’QTLs: ∼0.4 million genetic variants associated with alternative polyadenylation of target genes across 46 tissues from 467 individuals 3’QTLs could alter polyA motifs and RNA-binding protein binding sites 3’QTLs can be used to interpret ∼16.1% of trait-associated variants Many disease-associated 3’QTLs contribute to phenotype independent of gene expression