Fig. 1. Fluorescence in situ hybridization of BAC probes to chromosome arms in wild-type (A-D) and syn1 (E-H) meiocytes. Hybridization of BAC probes was detected with fluorescein-labeled streptavidin (green). Chromosomes were stained with PI (red). (A,E) Early leptotene; (B,F) pachytene; (C,G) early diplotene; (D,H) prometaphase. Normal-appearing chromosomes at zygotene, pachytene, diplotene or diakinesis were never observed in syn1 plants. Therefore, assignment of the stage of the cell cycle is approximate and based on chromosome morphology and the stage of surrounding cells in the anther. Bar, 5 µm.