[1]: 27 ), also known as pachynema, is the third stage of prophase I during meiosis, the specialized cell division that reduces chromosome number by half to produce haploid gametes.
These proteinaceous structures mark the sites of genetic crossover events between the non-sister chromatids that were initiated during zygotene.
[11] Pachytene is also a stage where a critical checkpoint operates to monitor proper chromosome synapsis and recombination.
[12] Once crossover events are stabilized, the synaptonemal complex disassembles and chromosomes begin to gradually desynapse as the cell transitions into the diplotene stage.
The pachytene stage is essential for the extensive genetic recombination and accurate chromosome segregation in meiosis.