During prophase I of meiosis I, the pairing of two homologous chromosomes is called the synapsis. Synapsis occurs due to the lengthwise pairing of homologous chromosomes with the help of a protein complex. The protein complex that connects the homologous chromosomes is called the synaptonemal complex.
Synapsis allows chromatid arms to exchange chromosomal segments by the process known as crossing over and helps in genetic recombination in the gametes.
