Which of the following sequence is correct about the five phases of Prophase I?

The correct answer is Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis

Explanation:

Meiosis I is divided into prophase I, metaphase I, anaphase I, and telophase I.

Prophase I of Meiosis I is further divided into - Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.

• Leptotene: The chromosomes become gradually visible under the light microscope. The chromosomes start to condense and achieve a compact shape.
• Zygotene: The pairing of homologous chromosomes in zygotene initiates a process called chromosomal synapsis, which is followed by the development of a complex structure known as the synaptonemal complex. The bivalent or tetrad complex is made up of two homologous chromosomes that have synaptically joined.
• Pachytene: During this stage, the four chromatids of each bivalent chromosome become distinct and clearly appear as tetrads. This stage is characterised by the appearance of recombination nodules, the sites at which crossing over occurs between non-sister chromatids of the homologous chromosomes.
• Diplotene: The beginning of diplotene is recognised by the dissolution of the synaptonemal complex and the tendency of the recombined homologous chromosomes of the bivalents to separate from each other except at the sites of crossovers. Chiasmata are the X-shaped structures that occur during separation.
• Diakinesis: Diakinesis is marked by the termination of chiasmata and assembly of the meiotic spindle to separate the homologous chromosomes. The nucleolus disappears and the nuclear envelope breaks down