[Non random position of metaphasic chromosomes. III. Position of chromosomes involved in constitutional translocations].

Autosome-autosome and sex chromosome-autosome constitutional translocations are analyzed in order to determine whether the affected chromosomes have a particular position in the spread metaphase. Except for one t (10;15) and for several t (X;autosome), the rearranged chromosomes and their normal homologues seem to have random positions. In so far as it has been demonstrated that the metaphase chromosome's positions reflect those of the interphase chromosomes, it is concluded that no specific ordering, transmissible cell generation after generation, exists. The position of the chromosomes would be determined after anaphase migration and would remain unchanged until the subsequent metaphase. Therefore, the rearrangements do not impose any particular topological constraints to the involved chromosomes. The only exceptions may concern the sex chromosomes and those carrying nucleolar organizers.