DNA probe is used in

Options

A. Gel electrophoresis
B. Northern blotting
C. DNA finger printiing
D. Interferon synthesis

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Probes**: A DNA probe is a fragment of DNA that is labeled (often with a radioactive or fluorescent tag) and is used to detect the presence of complementary sequences in a sample. The length of the probe can vary, typically ranging from 100 to 1000 bases.

2. **Applications of DNA Probes**: DNA probes are utilized in various molecular biology techniques to identify specific DNA sequences. They can be used for:
- **DNA Fingerprinting**: This technique uses DNA probes to identify individuals based on their unique DNA patterns.
- **Detection of Pathogenic Bacteria**: DNA probes can help identify the presence of specific pathogenic bacteria in a sample.
- **Gene Detection**: Probes can be used to determine whether certain genes are present in an individual, which is crucial for genetic testing.

3. **Analyzing the Options**:
- **Option A: Gel Electrophoresis**: This is a technique used to separate DNA fragments based on size, but it does not directly involve the use of DNA probes.
- **Option B: Northern Blotting**: This technique is used to study gene expression by detecting RNA, and while probes are used, this is not the primary application of DNA probes.
- **Option C: DNA Fingerprinting**: This is a direct application of DNA probes to identify individuals based on their unique DNA sequences. This option aligns with the primary use of DNA probes.
- **Option D: Interferon Synthesis**: This is unrelated to DNA probes as it involves the production of proteins in response to viral infections.

4. **Conclusion**: Based on the analysis of the options, the correct answer is **Option C: DNA Fingerprinting**.