Explain prophase I of meiosis.

* Prophase I is typically longer and more complex.
* It has been further subdivided into 5 phases based on chromosomal behaviour.
A) Leptotene : In this stage, compaction of chromosomes takes place and they are gradually visible under the light microscope.
B) Zygotene : In this stage, pairing of homologous chromosomes known as synapsis takes place. Synapsis is accompanied by protein known as synaptonemal complex. Pair of synapsed homologous chromosomes is called a bivalent.
C) Pachytene : Appearance of recombination nodules and crossing over occurs between non-sister chromatids of homologous chromosomes.
D) Diplotene : Dissolution of synaptonemal complex, separation of homologous chromosomes of bivalents except at the sites of crossing over.
E) Diakinesis : Terminalization of chiasmata, nucleolus and nuclear membrane disappears.