Pachytene and Diakinesis Behavior of the Isochromosomes 6 of Maize.

Complementary isochromosomes which shared homologies only for the centromere region and one or two adjacent chromomeres were rarely found associated at pachytene. It is therefore questioned whether the centromere plays an important specific role in the initiation of synapsis. It is also questioned whether centromere repulsion is a cause of diplotene separation and terminalization since the isochromosome univalent foldbacks assumed shapes typical of bivalents with chiasmata at diplotene and diakinesis.