A quantitative study of chiasma terminalization in the grasshopper Chorthippus jucundus

The possible existence of chiasma terminalization in the grasshopper Chorthippus jucundus was tested in four males by means of comparisons between chiasma locations at diplotene and metaphase I within L3, M4 and M5 bivalents. Diplotene cells were stained by a C-banding technique to recognize heterochromatic regions, especially the centromeric ones, whereas metaphase I cells were stained by a silver staining technique that visualizes a core-like structure that extends through each homologous chromosome. The core is very pronounced at kinetochores and forms cross-shaped configurations at chiasmata. No evidence of chiasma terminalization has been found.