During meiosis I, in which stage synapsis takes place?

Prophase I is subdivided into five phases, viz. Leptotene, Zygotene, Pachytene, Diplotene and Diakinesis.

Leptotene: During this stage, the chromosomes become gradually visible under a light microscope. Compaction of chromosomes continues throughout this phase.

Zygotene: Chromosomes start pairing together. This process is called synapsis. The paired chromosomes are called homologous chromosomes. The formation of synapsis is accompanied by the formation of the synaptonemal complex.

Pachytene: Recombination nodules appear. These nodules are the sites at which crossing over takes place between non-sister chromatids of the homologous chromosomes.

Diplotene: Synapotnemal complex is dissolved at this stage. The recombined homologous chromosomes of the bivalent separate from each other; except at the site of crossing over. The X-shaped structures; thus formed; are called chiasmata.

Diakinesis: Chiasmata is terminated at this stage.