Crossing over occurs during metaphase I of meiosis.
Crossing over, also known as genetic recombination, occurs during the prophase I stage of meiosis. More specifically, it takes place during the late prophase I (also known as the pachytene stage) when homologous chromosomes pair up and undergo a process called synapsis. During synapsis, non-sister chromatids from homologous chromosomes exchange genetic material through a process called crossing over.
