In which stage synaptonemal complex dissolves, chromatids become clear and bivalents are called tetrads

Options

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

Answer

To answer the question regarding the stage in which the synaptonemal complex dissolves, chromatids become clear, and bivalents are referred to as tetrads, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Stages of Meiosis**:
- Meiosis consists of two main divisions: Meiosis I and Meiosis II. The question pertains to the stages within Meiosis I, specifically during Prophase I.

2. **Identifying the Stages of Prophase I**:
- Prophase I is divided into several stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.

3. **Analyzing the Stages**:
- **Zygotene**: During this stage, homologous chromosomes begin to pair up, forming a synaptonemal complex. This is where the complex starts to build up, not dissolve.
- **Pachytene**: In this stage, crossing over occurs between non-sister chromatids, and the synaptonemal complex is still present.
- **Diplotene**: This is the key stage we are looking for. During Diplotene, the synaptonemal complex begins to dissolve. The homologous chromosomes start to separate but remain connected at points called chiasmata, where crossing over has occurred. The bivalents are now referred to as tetrads.
- **Diakinesis**: In this final stage of Prophase I, the chromosomes condense further, and the synaptonemal complex is completely gone, but the question specifically asks for when it begins to dissolve.

4. **Conclusion**:
- The correct answer to the question is **Diplotene**, as this is the stage where the synaptonemal complex dissolves, chromatids become clearer, and bivalents are referred to as tetrads.

### Final Answer:
The stage in which the synaptonemal complex dissolves, chromatids become clear, and bivalents are called tetrads is **Diplotene**.

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