Fig. 1.

Formation mechanisms of trisomy and UPD after meiotic and mitotic nondisjunction. iUPD formation by gamete complementation is not shown as it should be very rare, but the allelic patterns correspond to those of monosomic rescue. Possible typing results of four different molecular markers are shown to illustrate the role of their physical localization (close or far from the centromere on both arms) for the discrimination between hUPD and iUPD