The mitochondrial DNA differs from the nuclear DNA in

Options

A. Having association with histones
B. Being circular in nature
C. Having higher C-G ratio
D. All of these

Answer

To answer the question "The mitochondrial DNA differs from the nuclear DNA in," we will analyze the given options step by step.

### Step-by-Step Solution:

1. **Understanding Mitochondrial DNA (mtDNA) and Nuclear DNA (nDNA)**:
- Mitochondrial DNA is the genetic material found in mitochondria, while nuclear DNA is located within the nucleus of eukaryotic cells.

2. **Option 1: Association with Histones**:
- Histones are proteins that help package and organize DNA in the nucleus. Nuclear DNA is associated with histones, forming a structure called chromatin.
- In contrast, mitochondrial DNA does not associate with histones. Instead, it is packaged with different proteins that are not histones.
- **Conclusion**: This option is incorrect.

3. **Option 2: Being Circular in Nature**:
- Mitochondrial DNA is circular in shape, similar to the DNA found in prokaryotic cells.
- Nuclear DNA, on the other hand, is linear and organized into chromosomes.
- **Conclusion**: This option is correct.

4. **Option 3: Higher C-G Ratio**:
- The C-G ratio refers to the ratio of cytosine (C) to guanine (G) bases in the DNA. While mitochondrial DNA has a different base composition compared to nuclear DNA, it does not universally have a higher C-G ratio.
- This option does not accurately describe a consistent difference between mtDNA and nDNA.
- **Conclusion**: This option is incorrect.

5. **Option 4: All of These**:
- Since not all previous statements are correct, this option cannot be true.
- **Conclusion**: This option is incorrect.

### Final Answer:
The correct answer is **Option B: being circular in nature**.