890475.fig.004
Figure 4: Possible events associated with the initiation of synaptonemal complex (SC) formation. Formation of recombinational joint molecules between the homologous chromosomes (interhomologue joint molecule, IHJM) enables stable coupling between the homologous CENs and triggers centromeric SC initiation. This restrains an unknown inhibitory signal, X, which hitherto blocked SC initiation from the prospective CO sites.