During meiosis-I, in prophase I, firstly chromatin network condenses gradually which is visible as chromosomes under microscope. Homologous chromosomes pair up in a process called synapsis. Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes. The paired chromosomes move apart due to dissolution of the protein laden-synaptonemal complex. The actual point at which crossing over takes place is visualized as ' X ' shaped structure called chiasmata.