Fig. 3

Analysis of meiotic prophase I progression using surface spreads. a-e Examples of nuclei at each substage of prophase one labeled with SYCP3 (green) and DAPI (blue). a Nucleus in the leptotene substage showing chromosomes beginning to condense. b Nucleus in the zygotene substage showing homologous chromosomes beginning to come together and the synaptonemal complex starting to form. c A pachytene nucleus showing completion of synapsis. d A diplotene arrested nucleus showing chromosomes that have begun to separate but remain attached at sites of crossing over. e A late-diplotene/dictyate nucleus, with chromosomes condensed and at opposite poles. Scale bar = 20 μm. f Percent of oocyte nuclei in each stage of prophase one from 17.5 dpc to PND4 determined using the meiotic surface spread assay with SYCP3 staining. Approximately 200 nuclei were counted for each age of development