Question

The stage during which separation of the paired homologous chromosomes begins is

• A. Pachytene
• B. Diakinesis
• C. Diplotene
• D. Zygotene

Answer 1

The Correct Option is C

To determine the correct answer to the question, "The stage during which separation of the paired homologous chromosomes begins is," we need to understand the stages of meiosis, particularly Meiosis I, where homologous chromosomes are involved.

1. Overview of Meiotic Prophase I:
   • Leptotene: Chromosomes start condensing and become visible.
   • Zygotene: Chromosome homologs begin pairing (synapsis starts).
   • Pachytene: Crossing over occurs as homologous chromosomes are fully synapsed.
   • Diplotene: Synapsis ends, and homologous chromosomes start to separate but remain attached at chiasmata.
   • Diakinesis: Chromosomes further condense, and chiasmata migrate towards the ends.
2. Analysis of Options:
   • Pachytene: At this stage, homologous chromosomes are synapsed, and crossing over occurs. Separation does not start here.
   • Diakinesis: In this stage, homologous chromosomes are fully condensed and preparing for metaphase, but separation did not initiate here; instead, it’s final preparation before complete disjunction.
   • Diplotene: This is the correct answer because it is the stage where separation of homologous chromosomes begins as chiasmata become visible and start moving toward telomeres.
   • Zygotene: This stage involves pairing (synapsis) and not separation.
3. Conclusion: The separation of paired homologous chromosomes initiates during the Diplotene stage. Therefore, the correct answer is "Diplotene".