Synaptonemal complexes is a nucleoprotein structure. It is visible or found from-

Options

A. leptotene through diplotene
B. pachytene through diplotene
C. zygotene through pachytene
D. diplotene through metaphase

Answer

To answer the question regarding the visibility of synaptonemal complexes, we need to understand the stages of meiosis, particularly during prophase I. Here’s a step-by-step breakdown:

### Step-by-Step Solution:

1. **Understanding Meiosis Prophase I**:
- Meiosis prophase I is divided into five stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.

2. **Identifying Synaptonemal Complex Formation**:
- **Leptotene**: Chromosomes begin to condense, but synaptonemal complexes are not yet formed.
- **Zygotene**: This is where synapsis occurs, and synaptonemal complexes begin to form between homologous chromosomes.
- **Pachytene**: The synaptonemal complexes are fully formed, and tetrads (four chromatids) are visible. This is also where genetic recombination occurs.
- **Diplotene**: The synaptonemal complexes begin to dissolve, indicating the end of their presence.
- **Diakinesis**: The synaptonemal complexes have mostly disappeared, and the chromosomes are fully condensed and ready for metaphase.

3. **Determining Visibility**:
- Synaptonemal complexes are visible during the **Zygotene** and **Pachytene** stages. They start to dissolve in **Diplotene**, and by **Diakinesis**, they are no longer present.

4. **Conclusion**:
- Therefore, synaptonemal complexes are visible from **Zygotene through Pachytene**.

### Final Answer:
The correct option is: **Zygotene through Pachytene**.

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