Question

What marks the beginning of the diplotene?

Answer 1

Diplotene:

1. Prophase of ‘meiosis I’ is divided into five phases- leptotene, zygotene, pachytene, diplotene, and diakinesis.
2. In the zygotene phase, the homologous chromosomes pair together and a protein complex called ‘synaptonemal complex’ tightly joins the paired chromosomes. This is followed by pachytene phase in which crossing over takes place.
3. The beginning of the diplotene is marked by the dissolution of the synaptonemal complex and the propensity of the recombined homologous chromosomes to start separating from each other except at the crossover sites. This results in a formation of an X-shaped structure called ‘chiasmata’.