In which phase of meiosis-I does the process of disjunction take place?

Options

A. Prophase
B. Metaphase
C. Anaphase
D. Telophase

Answer

**Step-by-Step Solution:**

1. **Understanding Disjunction**: Disjunction refers to the process where chromosomes are separated and move towards opposite poles during cell division. This is a crucial step in ensuring that each daughter cell receives the correct number of chromosomes.

2. **Identifying Meiosis I Phases**: Meiosis I consists of several phases: Prophase I, Metaphase I, Anaphase I, and Telophase I. Each phase has distinct events that occur.

3. **Analyzing Prophase I**: In Prophase I, the chromatin condenses into visible chromosomes, and homologous chromosomes pair up. However, there is no separation of chromosomes at this stage.

4. **Analyzing Metaphase I**: In Metaphase I, homologous chromosomes are aligned at the equatorial plane of the cell. Again, there is no separation occurring during this phase.

5. **Analyzing Anaphase I**: Anaphase I is the phase where disjunction occurs. During this phase, homologous chromosomes are pulled apart and move towards opposite poles of the cell. This is the key event where the separation of chromosomes takes place.

6. **Analyzing Telophase I**: In Telophase I, the separated chromosomes reach the poles, and the nuclear membrane may begin to reform. However, this phase does not involve the disjunction process itself.

7. **Conclusion**: Based on the analysis, the correct phase of meiosis I in which disjunction occurs is Anaphase I.

**Final Answer**: Disjunction takes place in Anaphase I of meiosis I.

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