Defective meiotic chromosome organization in AtCTF7- RNAi. Acid spreads of male meiotic chromosomes stained with DAPI. (A-H) Untreated AtCTF7-RNAi line, (I-L) AtCTF7-RNAi line treated with dexamethasone. (A) Meiotic interphase. (B) Leptotene. (C) Zygotene. (D) Pachytene showing complete chromosome synapsis. (E) Late diplotene showing 5 partially condensed bivalents. (F) Diakinesis showing 5 condensed bivalents. (G) Metaphase I showing 5 aligned bivalents. (H) Metaphase II showing two sets of 5 aligned chromosomes. (I) Early prophase stage showing few thread-like segments and many discontinuities. (J) Early prophase stage with discontinuous and fragmented chromatin. (K) Mid-prophase showing unpaired, discontinuous chromatin and absence of synizetic knot. (L) Late prophase stage, showing condensed and fragmented chromatin.