Question

The stage during which separation of the paired homologous chromosome begins is:

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

Answer 1

The correct option is C

Diplotene

The correct option is C.

Explanation of the correct option:

1. Homologous chromosomal pairs start to separate and migrate away from one another, with the exception of at chiasmata, in the late stage of prophase I of meiosis I.
2. Meiosis is a type of cell division that creates gametes, or sex cells, with a variety of genetic make-up.
3. Desynapsis and chiasmata development are features of the diplotene stage.
4. Synaptonemal complexes that were generated during zygotene disintegrate in the diplotene stage, and homologous chromosomal desynapsis begins.
5. Except at the places of crossing over known as chiasmata, homologous chromosomes are distinct from one another.

Explanation of the incorrect options:

Option A:

Following leptotene, zygotene is the stage of meiosis during which homologous chromosomes start to couple.

Option B:

1. The third stage of meiosis' prophase, pachytene, comes after zygotene.
2. During this time, the paired chromosomes shorten and thicken, each of their two chromatids separates, and there may be an exchange of segments between chromatids.

Option D:

After diplotene, the fifth and final stage of the prophase of meiosis—diakinesis—occurs when homologous chromosomal separation is complete and crossing over has taken place.

Final answer:
The stage during which the separation of the paired homologous chromosome begins is diplotene.