Fig. 4. Telomeres exhibit a prolonged attachment to the nucleolus in the meiocytes of ask1-1 plants. (a) Telomere FISH on meiotic chromosomes in wild-type (A-D) and ask1-1 (E-H) cells prepared using standard fixation techniques and chromosome spreading. (A,E) Interphase; (B,F) leptotene; (C,G) zygotene; (D,H) pachytene. No significant differences are observed in the distribution of telomere signals. (b) Telomere FISH on meiotic chromosomes in paraformaldehyde-fixed wild-type (A-D) and ask1-1 (E-H) cells. Arrows indicate the position of the nucleolus. (A,E) Interphase; (B,F) leptotene; (C,G) zygotene; (D,H) pachytene. Note the persistent association of telomere signals with the nucleolus in ask1-1 meiocytes but not in wild-type meiocytes. Assignment of meiotic stages in ask1-1 is based on chromosome morphology and the stage of the surrounding tapetal cells. Bars, 10 µm.