Question

What are the sub-stages of prophase I of Meiosis I? Explain briefly.

Answer 1

Meiosis:

1. A kind of cell division, which leads to the formation of four daughter cells with half the number of chromosomes of the parent cell is meiosis.
2. In Meiosis I, the pair of homologous chromosomes separates and the diploid cell gets reduced to the haploid stage.
3. Meiosis I is differentiated into many phases, that is, prophase I, metaphase I, anaphase I, and telophase I.

Prophase I is further divided into sub-stages:

1. Leptotene: In this stage, the initiation of chromosome condensation takes place and it attains a composite form.
2. Zygotene: In this, the homologous chromosomes pairs, the process is called chromosomal synapsis. It is followed by the generation of a composite composition called the synaptonemal complex.
3. Pachytene: In this stage, the crossing over of non-sister chromatids of homologous chromosomes takes place. The chromosomes stay associated at the crossing-over sites.
4. Diplotene: It marks the synaptonemal complex dissolution and separation of the homologous chromosomes except at the crossing over sites. The formation of X-shaped compositions takes place at the time of separation called chiasmata.
5. Diakinesis: It is signified by the end of chiasmata and assembly of the meiotic spindle to distinguish the homologous chromosomes. The disappearance of nucleolus takes place and the nuclear envelope dissociates.