The stage in which chiasmata can be seen is

Options

A. Leptotene
B. Zygotene
C. Pachyene
D. Diakinesis

Answer

**Step-by-Step Solution:**

1. **Understanding Chiasmata**: Chiasmata are X-shaped structures that form during meiosis when homologous chromosomes exchange genetic material through a process called crossing over. This occurs during prophase I of meiosis.

2. **Identifying the Stages of Prophase I**: Prophase I of meiosis consists of several stages:
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis

3. **Analyzing Each Stage**:
- **Leptotene**: This is the initial stage where chromosomes begin to condense, but chiasmata are not visible.
- **Zygotene**: In this stage, homologous chromosomes begin to pair up (synapsis), but chiasmata are still not visible.
- **Pachytene**: This is where crossing over occurs, and while the process is happening, the chiasmata are not distinctly visible yet.
- **Diplotene**: At this stage, the homologous chromosomes begin to separate, and the chiasmata become visible as the chromosomes pull apart.
- **Diakinesis**: This is the final stage of prophase I where the chromosomes are fully condensed, and the chiasmata remain visible until the end of prophase I.

4. **Conclusion**: The stage in which chiasmata can be seen is **Diplotene**, and they remain visible into **Diakinesis**. However, the question specifically asks for the stage where they can first be seen, which is **Diplotene**.

**Final Answer**: The stage in which chiasmata can be seen is **Diplotene**.

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