Schematic presentation of the DLK1-DIO3 imprinting cluster at chromosome 14q32.2 . The DLK1-DIO3 cluster contains three paternally expressed protein coding genes (light gray arrows) and multiple maternally expressed noncoding RNAs (dark gray arrows). The respective inactive gene copies are not shown. It is debated whether BEGAIN and DIO3-AS (white) are biallelically expressed. Arrowheads indicate the direction of transcription. Imprinting is regulated by differentially methylated regions (DMR), the IG DMR and the MEG3 DMR, methylated at the paternal allele (black circle) and unmethylated at the maternal allele (white circle). The relative localizations of selected microRNAs and the C/D RNA unit are indicated by dashed arrowheads.