Which one of the following human genes has the longest stretch of DNA `(~24Mb)`?

Options

A. Globin gene
B. Histone gene
C. Dytrophin gene
D. Insulin gene

Answer

To solve the question of which human gene has the longest stretch of DNA (~24Mb), we will analyze the options provided and identify the gene with the longest sequence.

### Step-by-Step Solution:

1. **Understand the Options**: The options given are:
- A) Globin gene
- B) Histone gene
- C) Dystrophin gene
- D) Insulin gene

2. **Research Each Gene**:
- **Globin Gene**: This gene is involved in the production of hemoglobin, which carries oxygen in the blood. The globin gene cluster is relatively small compared to others.
- **Histone Gene**: Histone genes are responsible for producing proteins that help package DNA into structural units called nucleosomes. These genes are also not very long.
- **Dystrophin Gene**: This gene is known for its significant length. It encodes the dystrophin protein, which plays a crucial role in muscle function by connecting the cytoskeleton of muscle fibers to the extracellular matrix. The dystrophin gene is approximately 24 megabases (Mb) long, making it the longest known human gene.
- **Insulin Gene**: The insulin gene is involved in the production of insulin, a hormone that regulates glucose levels in the blood. This gene is relatively small compared to the dystrophin gene.

3. **Identify the Longest Gene**: After analyzing the lengths and functions of each gene, it is clear that the dystrophin gene is the longest, with a stretch of DNA of about 24Mb.

4. **Conclusion**: The gene with the longest stretch of DNA among the options provided is the **Dystrophin gene**.

### Final Answer:
The correct answer is **C) Dystrophin gene**.

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