Heatmap illustrating MII YMA and AMA oocyte classification. Colour gradient ranges from dark blue to yellow. Horizontal bars (on the top of heatmap) represent the maternal age class of the oocytes MII YMA (purple) and MII AMA (orange). Ontological cluster identification is facilitated by the dendrogram (left). The ontological term and the type of the ontology terms are illustrated on the right. AMA, advanced maternal age; BP, biological process; CC, cellular component; FC, fold change; GO, gene ontology; MF, molecular function; MII oocyte, metaphase II oocyte; YMA, young maternal age.