Identification of Imprinted Genes and Their Differentially Methylated Regions in Porcine

Genomic imprinting is an epigenetic mechanism that leads to parent-specific gene expression. A number of imprinted genes have been identified in humans and mice but fewer genes have been described as imprinted in pig. In the study, 59 porcine candidate imprinted genes were obtained by bioinformatics analysis. Among them, Grb10, Slc22a3 and Slc22a18 were selected for molecular cloning and expression pattern analysis. And, single-nucleotide polymorphism-based methods were performed to identify their imprinting status. We found that Grb10 and Slc22a18 were imprinted in pig and their differentially methylated regions were further determined by bisulfite sequencing PCR. With this work we advance the field of genomic imprinting by expanding the list of imprinted genes in pig and demonstrate a feasible and effective method to characterize imprinted genes in mammalians.