Genetic variability of microRNA genes in farm animals

Abstract

MicroRNAs (miRNAs) are a class of non-coding RNAs that plays an important role in posttranscriptional regulation of target genes. Regulation requires complementarity between the target mRNA and the miRNA seed region, which is responsible for their recognition and binding. Previous studies in human and mouse have shown that variability of miRNA gene (miR-SNPs) might interfere with its function resulting in phenotypic variation. Polymorphisms within miRNA genes could represent biomarkers for phenotypic traits important in farm animals. The aim of this study was to: 1) update previously developed web-based tool for identification of polymorphisms within miRNA genes (miRNA SNiPer), 2) systematically collect polymorphisms of miRNA genes in pig, cattle, chicken, and horse, and 3) experimentally validate SNPs within miRNA seed regions (miR-seed-SNPs) in cattle. Using miRNA SNiPer tool, polymorphisms within 32 mature miRNA regions, including 12 miR-seed-SNPs, were identified in pig, cattle, and chicken. Bovine miRseed SNPs were chosen for experimental validation. The bta-mir-2313 locus was shown to be very polymorphic, therefore we validated one SNP with previously unknown validation status within the mature seed region in population of Slovenian Simmental cattle. Additionally, two SNPs in corresponding pri-miRNA were identified. Results of this study can serve researchers for follow up hypothesis-driven experimental studies to evaluate the phenotypic effect of identified miRNA genetic variability in vertebrates.