Repulsion of homologous chromosomes takes place in

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the stage in meiosis where the repulsion of homologous chromosomes occurs.

2. **Identifying Meiosis Stages**: Meiosis consists of several stages, particularly in prophase I, which includes leptotene, zygotene, pachytene, diplotene, and diakinesis.

3. **Analyzing Each Option**:
- **Zygotene**: This is the second stage of prophase I where homologous chromosomes begin to pair up (synapsis). Therefore, repulsion does not occur here. **(Incorrect)**
- **Leptotene**: This is the first stage of prophase I where chromosomes start to condense and become visible. Homologous chromosomes are not yet paired. **(Incorrect)**
- **Diakinesis**: This is the last stage of prophase I where the chiasmata (points of crossing over) are resolved, and chromosomes are fully condensed. However, this stage does not primarily focus on repulsion. **(Incorrect)**
- **Pachytene**: This is the fourth stage of prophase I where homologous chromosomes are paired as tetrads and crossing over occurs. It is during this stage that the repulsion of homologous chromosomes begins as they start to separate after crossing over. **(Correct)**

4. **Conclusion**: The correct answer is **Pachytene**, where the repulsion of homologous chromosomes takes place.

---