Prophase-I of meiosis has been divided into five sub-stages which occur in the sequence as: Leptotene → Zygotene → Pachytene → Diplotene → Diakinesis. Synapsis i.e., pairing of homologous chromosomes occurs during zygotene. Crossing over i.e., exchange of chromatid segments occurs during pachytene. Terminalisation of chiasmata i.e., shifting of chiasmata towards the ends of chromosomes and complete disappearance of nucleolus take place during diakinesis.