Prophase of the first meiotic division is typically longer on complex. It is subdivided into 5 phases , leptotene, zygotene, pachytene,diplotene and diakinesis. Which of the following statements is not correct of these phases ?

Options

A. The formation of synaptonemal complex is seen during zygotene stage
B. The stage of pachytene is characterised by appearance of recombination nodules
C. Diplotene stage is marked by terminalisation of chiasmata
D. The compaction of chromosomes continues throughout the leptotene

Answer

To solve the question regarding the prophase of the first meiotic division and the correctness of statements about its sub-phases, we will analyze each statement provided in the question systematically.

### Step-by-Step Solution:

1. **Understanding Prophase of Meiosis**:
Prophase I of meiosis is divided into five sub-phases: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis. Each phase has distinct characteristics and events.

2. **Analyzing Each Statement**:
- **Statement 1**: "Formation of synaptonemal complex is seen during Zygotene stage."
- **Analysis**: This statement is correct. The synaptonemal complex forms during Zygotene, stabilizing homologous chromosomes for pairing.

- **Statement 2**: "The stage of Pachytene is characterized by appearance of recombination nodules."
- **Analysis**: This statement is also correct. During Pachytene, crossing over occurs, and recombination nodules appear as a result of this genetic exchange.

- **Statement 3**: "The Diplotene stage is marked by terminalization of chiasmata."
- **Analysis**: This statement is incorrect. The terminalization of chiasmata occurs during Diakinesis, not Diplotene. In Diplotene, chiasmata are formed, but they have not yet terminalized.

- **Statement 4**: "The compactation of chromosomes continues throughout the Leptotene."
- **Analysis**: This statement is correct. Leptotene is characterized by the condensation and coiling of chromatin fibers, indicating that chromosome compactation is ongoing.

3. **Conclusion**:
The statement that is not correct is **Statement 3**: "The Diplotene stage is marked by terminalization of chiasmata." This process occurs in the subsequent stage, Diakinesis.

### Final Answer:
The incorrect statement is **Statement 3**.

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