In which step of DNA profiling, nitrocellulose membrane is used ?

Options

A. Denaturation
B. Autoradiography
C. Blotting
D. DNA amplification

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Profiling**: DNA profiling is a technique used to identify individuals based on their unique DNA characteristics. It involves several steps including extraction, fragmentation, separation, and analysis.

2. **Extraction of DNA**: The first step in DNA profiling is the extraction of DNA from a sample. This is where the DNA is isolated from cells.

3. **Fragmentation of DNA**: The extracted DNA is then treated with restriction enzymes, which cut the DNA into smaller fragments. This is crucial for subsequent analysis.

4. **Electrophoresis**: After fragmentation, the DNA fragments are separated using a technique called electrophoresis. This process sorts the fragments based on their size, allowing for a clearer analysis of the DNA.

5. **Blotting**: Once the DNA fragments are separated, they need to be transferred onto a solid medium for further analysis. This is where the nitrocellulose membrane comes into play. The process of transferring the DNA fragments from the gel to the nitrocellulose membrane is known as "blotting," specifically Southern blotting in this context.

6. **Incubation with Probes**: After blotting, the nitrocellulose membrane is incubated with labeled probes that bind to specific DNA sequences. This step is essential for detecting the presence of particular DNA fragments.

7. **Analysis**: Finally, the membrane is analyzed, often using autoradiography, where X-ray film is used to visualize the bound probes, revealing the DNA fragments.

**Conclusion**: The nitrocellulose membrane is used in the blotting step of DNA profiling.

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