Chiasmata or X-shaped structures become visible during

Options

A. Diplotene stage
B. Zygotene stage
C. Pachytene stage
D. Leptotene stage

Answer

To solve the question "Chiasmata or X-shaped structures become visible during?", we need to understand the stages of prophase 1 of meiosis and the specific events that occur in each stage.

### Step-by-step Solution:

1. **Identify the Stages of Prophase 1**: Prophase 1 of meiosis is divided into five stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.

2. **Understand Each Stage**:
- **Leptotene**: This is the first stage where chromosomes begin to condense and become visible. No chiasmata are formed here.
- **Zygotene**: In this stage, homologous chromosomes begin to pair up, a process known as synapsis. Chiasmata are not yet visible.
- **Pachytene**: During this stage, crossing over occurs between non-sister chromatids, but chiasmata are still not distinctly visible.
- **Diplotene**: This is the stage where the synaptonemal complex begins to dissolve, and chiasmata become visible. This is the key stage for the visibility of chiasmata.
- **Diakinesis**: This is the final stage of prophase 1 where the chromosomes are fully condensed, but the chiasmata are already visible from the previous stage.

3. **Determine the Correct Answer**: Since chiasmata become visible during the diplotene stage, the correct answer to the question is **Diplotene stage**.

### Final Answer:
Chiasmata or X-shaped structures become visible during the **Diplotene stage** of prophase 1 in meiosis.

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