Final answer:
Synapsis occurs during the prophase I phase of meiosis I, where homologous chromosomes tightly pair together with the help of a synaptonemal complex and cohesin proteins.
Step-by-step explanation:
In what phase would you find synapsis occurring? Synapsis occurs during the prophase I stage of meiosis I.
Early in prophase I, before the chromosomes can be seen clearly microscopically, the homologous chromosomes come together to form a synapse. They are bound tightly together and in perfect alignment by a protein lattice known as a synaptonemal complex, and by cohesin proteins at the centromere. This tight pairing is essential for the process of crossing over where genetic material is exchanged between chromosomes, thereby contributing to genetic diversity.
As prophase I progresses, the synaptonemal complex begins to break down and the chromosomes condense further. By the end of prophase I, the homologous chromosomes, now referred to as tetrads due to the visibility of the four sister chromatids, are held together at specific locations called chiasmata.