Stages in proper sequence of prophase I are

Options

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

Answer

To determine the correct sequence of stages in Prophase I of meiosis, we need to identify and arrange the five sub-phases in the correct order. Here’s the step-by-step solution:

### Step-by-Step Solution:

1. **Identify the Stages of Prophase I**: Prophase I consists of five distinct stages:
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis

2. **Understand Each Stage**:
- **Leptotene**: This is the first stage where chromosomes become visible as thin threads. Each chromosome consists of two sister chromatids.
- **Zygotene**: In this stage, homologous chromosomes begin to pair up in a process called synapsis.
- **Pachytene**: This stage is characterized by the occurrence of crossing over, where genetic material is exchanged between homologous chromosomes.
- **Diplotene**: Here, the homologous chromosomes begin to separate but remain connected at points called chiasmata where crossing over occurred.
- **Diakinesis**: This is the final stage of Prophase I where the chromosomes condense further and the nuclear envelope breaks down, preparing for metaphase.

3. **Arrange the Stages in Sequence**: Based on the understanding of each stage, the correct sequence is:
- Leptotene → Zygotene → Pachytene → Diplotene → Diakinesis

4. **Select the Correct Option**: From the options provided, the sequence that matches our arrangement is:
- **Option A**: Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis.

### Final Answer:
The stages in proper sequence of Prophase I are: **Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.** Therefore, the correct answer is **Option A**.

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