In meiosis crossing over is initiated at

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding Meiosis**: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in four haploid cells from one diploid cell. It consists of two consecutive divisions: meiosis I and meiosis II.

2. **Identifying the Stages of Meiosis**: Meiosis I includes several stages: Prophase I, Metaphase I, Anaphase I, and Telophase I. Prophase I is further divided into five substages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.

3. **Crossing Over**: Crossing over is the process where homologous chromosomes exchange genetic material. This occurs during the pairing of homologous chromosomes.

4. **Location of Crossing Over**: The process of crossing over is initiated during the Pachytene stage of Prophase I. During this stage, homologous chromosomes are closely associated and form a structure known as the synaptonemal complex, which facilitates the exchange of genetic material.

5. **Conclusion**: Therefore, the correct answer to the question "In meiosis, crossing over is initiated at" is the Pachytene stage.

**Final Answer**: Crossing over is initiated at the Pachytene stage of meiosis.

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