Non random position of metaphasic chromosomes: a study of radiation induced and constitutional chromosome rearrangements.

The rearranged chromosomes derived from reciprocal translocations or dicentric-acentric formations, observed 48 h after their induction by irradiation at Go phase, have a clear tendency to be closer together than their normal homologues. This tendency disappears in longer cultures, and does not exist when many different constitutional reciprocal translocations are considered together. It indicates that the chromosomes having exchanged segments remain adjacent at the following metaphase, and thus, that metaphase plates reflect, at least partially the interphase arrangement of chromosomes.