Chiasmata appears during :-

Options

A. Diakinesis
B. Synaptotene
C. Diplotene
D. Leptotene

Answer

To determine when chiasmata appear during the cell cycle, we need to analyze the different stages of meiosis, specifically during prophase I. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Understanding Chiasmata**: Chiasmata are the points where homologous chromosomes are attached to each other during meiosis. They are crucial for the process of crossing over, where genetic material is exchanged between homologous chromosomes.

2. **Identifying Stages of Meiosis**: Meiosis consists of several stages, particularly in prophase I, which is divided into five substages: leptotene, zygotene, pachytene, diplotene, and diakinesis.

3. **Analyzing Each Stage**:
- **Leptotene**: This is the first stage of prophase I where chromosomes begin to condense, but chiasmata do not appear here.
- **Zygotene**: In this stage, homologous chromosomes begin to pair up and form synaptonemal complexes, but chiasmata are not yet visible.
- **Pachytene**: This is the stage where crossing over occurs, and chiasmata begin to form as the homologous chromosomes exchange genetic material.
- **Diplotene**: In this stage, the synaptonemal complex dissolves, and the homologous chromosomes start to separate but remain connected at the chiasmata.
- **Diakinesis**: This is the final stage of prophase I where the chromosomes condense further, and the chiasmata are still present but the homologous chromosomes are preparing to separate.

4. **Conclusion**: Chiasmata are first clearly visible during the **diplotene** stage of prophase I, where the crossing over has occurred, and the homologous chromosomes are held together at these points.

### Final Answer:
Chiasmata appear during **Diplotene** stage of prophase I in meiosis.

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