Ta ZYP1 localisation during sub-stages of prophase I in wild-type and ph1b mutant bread wheat. In Chinese Spring wild-type meiocytes, Ta ZYP1 (green) first appears as faint punctuate foci that localise to chromatin during leptotene. Ta ZYP1 signal expands from these foci to form short tracts in zygotene before lengthening and condensing to form long thick tracts along the synapsing homologous chromosomes during pachytene. The Ta ZYP1 signal diminishes significantly by diplotene and is absent in diakinesis. Spatial localisation of Ta ZYP1 in the ph1b mutant was similar to wild-type but differed temporally. The Ta ZYP1 signal remained as punctuate foci until the zygotene-pachytene transition before lengthening of the signal into short tracts were observed. The signal of Ta ZYP1 also persisted into diplotene at higher levels when compared to wild-type. Ta ASY1 (red) was used as a marker of early meiotic events. Chromatin (blue) was counter-stained with DAPI. Scale bars, 7.5 μm.