Structure of the centromere region in urodelan chromosomes was studied by light microscopy. The centromere region can not be seen as a particular structure in routine cytological preparations. Published works employing the modified cytological technique for light microscopy presented a quadruple structure or a spotted structure. However, there are still problems on the results since the figures have not given persuaded visualization in comparable to the electron microscopy.
Large sized chromosomes in urodelan cells were favorable to observe more detail structure than the mammalian chromosomes. In squashed preparation of uncolchicinized chromosomes of Cynops pyrrhogaster, the majority of chromosomes in the cell showed the stretched-out centromere at metapahse. The centromere region was raised to outside toward the poles on opposite side of sister chromatid. The structure was quite unlike with the previous studies which were prepared by rather violent treatment for the chromosome details. The result indicated that the possibility of destructive effects by the cytological treatments, such as colchicine and hypotonic solution, have disturbed the illustration of a real feature of the delicate centromeres.