Prophase I of meiosis is of longest duration and is further subdivided into five sub phases: leptotene, zygotene, pachytene, diplotene, diakinesis. Leptotene shows bouquet formation. The pairing of homologous chromosome or synapsis occurs in zygotene. Crossing over occurs in pachytene. Chiasmata formation occurs in diplotene, and terminalisation occurs in diakinesis.