The exchange of genes between two homologous chromosomes is known as chromosomal crossover or crossing over. This exchange between non-sister chromatids results in the recombinant chromosomes during sexual reproduction. Known to be one of the final stages of genetic recombination, it takes place in the pachytene stage of prophase I of meiosis during the phenomena of synapsis.
The crossing over takes place when the matching areas on the matching chromosomes disconnect to reconnect to other chromosomes.
