Prdm9 binding to satellite-DNA may facilitate its heterochromatinization by virtue of its transcriptional activity (Figure 7A), and alterations of Prdm9's binding specificity could allow it to act on a wider array of satellite-DNAs, consistent with its semi-dominant effect in hybrid sterility and human azoospermia. Here, PRDM9 is linked to Azoospermia.