Sequential study of synaptonemal complexes in mouse spermatocytes by light and electron microscopy

Synaptonemal complex (SC) studies in male mice from the beginning of meiosis to its completion (7-40 days of age) indicate: (1) the existence of a leptotene stage with fragmented and completely unpaired axial elements; (2) that synapsis begins at several different initiation points of the axial elements, resulting in X-shaped and Y-shaped configurations; (3) that interlocking of axial elements at zygotene is a normal phenomenon; and (4) that zygotene (presynaptic) and diplotene (postsynaptic) configurations are different from each other. © 1985 Dr W. Junk Publishers.