Chromosome movement during meiotic prophase in crane‐fly spermatocytes: III. Microtubules and the effects of Colcemid, nocodazole, and vinblastine

The effects of Colcemid, nocodazole, and vinblastine on microtubules and on the movement of chromosomes during late diakinesis were investigated in spermatocytes of the crane fly Nephrotoma suturalis. The kinds of movements observed in untreated cells—sex bivalent rotations, sex bivalent excursions, and rotations and positional changes of autosomal bivalents—also were observed in drug‐treated cells. These results were obtained in living cells in which the disruption and inhibition of microtubule assembly had been confirmed with polarized light microscopy. Effects of Colcemid and nocodazole also were assessed in fixed cells using electron microscopy. The results are in agreement with a hypothesis that microtubules are not a force‐generating component of the molecular machinery that brings about prophase movements.