Fig. 6. Chromosome entanglement and fragmentation observed in Atmnd1 mutants depends on SPO11-1. Comparison of meiotic progression in the spo11-1 mutant (A-F) and in the Atmnd1 spo11-1 double mutant (G-L). (A,G) Zygotene-like stage. No typical pachytene cells were detected, and only unsynapsed chromosomes were observed in the pachytene-like stage (B,H). In diakinesis (C,I), ten condensed univalents are visible. (D,J) Anaphase I. (E,K) Metaphase II. (F,L) Polyads. Chromosomes are stained with DAPI. Bar, 10 µm.