THE SYNAPTONEMAL COMPLEX IN THE BIPARTITION DIVISION OF THE RADIOLARIA AULACANTHA SCOLYMANTHA

A tripartite structure having the same morphological features (two lateral elements and a central element connected by thin threads) as synaptonemal complex, is present during a part of the bipartition division. The first appearance consists of an axial element inside each chromosome, first connected with the nuclear envelope; when the chromosomes lie side by side, two by two, the axial elements are parallel, and when close to each other, thin filaments connect them and give the typical tripartite structure; this structure persists for some time and then disaggregates giving isolated elements which persist to prometaphase. In the present case, we have no proof which allows us to interpret this kind of division as a meiotic one. We considered the synaptonemal complex observed here as a structure which exists between paired chromosomes, a structure which plays a role in a process of depolyploidisation.