The PolymiRTS database was developed to systematically identify DNA polymorphisms in miRNAs and miRNA target sites (PolymiRTS), and elucidate their potential links to molecular, physiological, behavioral and disease phenotypes. The original version of the PolymiRTS database (19) focused on SNPs in putative miRNA target sites, as few miRNA target sites had been experimentally determined. However, in recent years, there has been both extensive use of existing experimental techniques and development of novel high-throughput methods that identify miRNA target sites, and we have expanded the PolymiRTS database to include these experimentally supported sites (20). While these experiments have greatly increased understanding of miRNA targeting, they did have limitations. Some high- (e.g. microarray) (21) and low-throughput (e.g. luciferase reporter assay) (22) experimental techniques determine miRNA–mRNA target pairs but do not provide specific binding locations, while CLIP-seq experiments (e.g. HITS-CLIP and PAR-CLIP) (23,24) identify specific binding locations within mRNAs but not the miRNAs that bind to the locations. Therefore, these experiments still required predictions based on sequence complementarity to determine either the specific binding location or the binding miRNA. In contrast, a recent
