Lampbrush chromosomes are also called displotene chromosomes because they

Options

A. Show chiasmata
B. Resemble diplotene chromosomes
C. Are in permanent diplotene stage
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding Lampbrush Chromosomes**: Lampbrush chromosomes are specialized structures observed during the prophase of meiosis, particularly in the diplotene stage. They are named for their unique appearance, which resembles a lamp brush.

2. **Identifying the Stage**: These chromosomes are found in the diplotene stage of prophase I of meiosis. During this stage, homologous chromosomes begin to separate, but their sister chromatids remain attached at points called chiasmata.

3. **Characteristics of Lampbrush Chromosomes**:
- They exhibit chiasmata, which are the points where crossing over occurs between homologous chromosomes.
- They are in a permanent diplotene state, meaning they maintain this structure throughout the diplotene stage of meiosis.
- Their structure allows for active transcription of genes, which is why they are often found in oocytes of various animals (except mammals).

4. **Conclusion**: Based on the characteristics and the definition of lampbrush chromosomes, they are indeed called diplotene chromosomes because they show chiasmata, resemble diplotene chromosomes, and are in a permanent diplotene state. Therefore, the correct answer is "all the above."

**Final Answer**: Lampbrush chromosomes are also called diplotene chromosomes because they show chiasmata, resemble diplotene chromosomes, and are in a permanent diplotene state. Thus, the answer is "all the above."

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