Fig. 6.

The course of meiotic division in Dibothriocephalus latus after FISH with 18S rDNA probe (red) counterstained with DAPI (blue). (A) Interphase nucleus with a large nucleolus and 3 18S rDNA clusters. (B) Leptotene. (C–G) Pachytene nuclei showing irregular pairing of spermatocyte chromosomes carrying rDNA genes; (C, D) pachytene with NOR-bearing triplet No. 7 in form of 1 univalent and 1 bivalent or (E–G) 3 univalents. (H) Metaphase II. (I) Secondary spermatocyte, the early stage of spermiogenesis (scale bar = 10 μm). Abbreviations: FISH, fluorescence in situ hybridization; NOR, nucleolar organizer region