Methylation at paternally imprinted gene clusters. Methylation of DMRs at the H19 (A) and DLK1 (B) clusters in extraembryonic and somatic tissues was obtained by bisulfite sequencing. Although parental/offspring samples were not available, allelic distinction between methylated/unmethylated alleles is consistent between tissues from the same individual and supports imprinting, not random allelic inactivation, at these loci. SNPs around each DMR were used to make the allelic distinctions shown.SNPs around each DMR were used to make the allelic distinctions shown.