Fig. 2. Meiotic MIC reorganization in wild type and in mutants. (A) Micrographs with each panel showing the MICs and MACs of a pair of conjugating cells (DAPI staining). (a) During wild-type prophase, the MIC progressively elongates and reaches its maximal extension at stage IV. From then on, it shortens again, and chromatin condenses and reaches maximal condensation at stage VI, which corresponds with diakinesis–metaphase-I. This is followed by a first and a second meiotic division. (b) In the hop2A mutant, MIC development is normal up to stage V. At stage VI, condensed chromatin entities, which are more numerous than in the wild type, appear. (c) In the spo11 mutant, stage II is normal but the shape of stage-III MICs is irregular and their ends do not taper. Stage IV is missing. Instead, MICs progress from an aberrant stage III directly to stage V. (d) Cisplatin treatment restores full elongation of the MICs. Scale bar: 10 µm. (B) Meiotic time-courses of wild-type, hop2A and spo11 meiosis. Whereas in the hop2A mutant, meiosis progresses similarly to wild type, there are no stage IV crescents formed in the spo11 deletion mutant. Aberrant stage-III MICs (dark shading) directly progress to stage V. The heights of the columns represent the percentages of cells in each stage for each time point. At least 200 MICs were evaluated for each time point.