What is the function of the chiasmata in meiosis?
Chiasmata become cytologically visible during diplotene and diakinesis after synaptonemal complex disassembly, appearing as cross-shaped connections between homologs under microscope. They represent late consequence of crossover recombination established chemically in pachytene between non-sister chromatids, where exchange of DNA segments creates physical interlock. Cohesion between sister chromatids distal to crossover site mediated by cohesin Rec8 maintains association, converting molecular exchange into durable tether linking homologs. This tether provides resistance to spindle pulling forc
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 21: Chiasmata and Homolog Cohesion.