In meiosis-I condensation and coiling of chromatin fibres started during

Options

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

Answer

To determine when the condensation and coiling of chromatin fibers start during meiosis-I, we need to analyze the stages of prophase I. Here’s the step-by-step solution:

### Step 1: Understand Meiosis I
Meiosis I is divided into several stages, and the first stage is prophase I, which is further subdivided into five distinct phases.

### Step 2: Identify the Phases of Prophase I
The five phases of prophase I are:
1. Leptotene
2. Zygotene
3. Pachytene
4. Diplotene
5. Diakinesis

### Step 3: Analyze Each Phase
- **Leptotene**: Chromosomes start to condense and become visible, but they are not fully coiled yet.
- **Zygotene**: Homologous chromosomes begin to pair up (synapsis) but still not fully condensed.
- **Pachytene**: Crossing over occurs, and chromosomes are more condensed than in leptotene and zygotene.
- **Diplotene**: Chromosomes begin to separate but are still connected at chiasmata.
- **Diakinesis**: This is the final stage of prophase I where chromosomes are fully condensed and maximally coiled.

### Step 4: Conclusion
The condensation and coiling of chromatin fibers start during **diakinesis**, which is the last stage of prophase I.

### Final Answer
The correct answer is **diakinesis**.

---