The technique used for separation of DNA fragment is:

Options

A. autoradiography
B. gel electrophoresis
C. microinjection
D. gel-filtration chromatography

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks for the technique used for the separation of DNA fragments.

2. **Evaluating the Options:**
- **Option 1: Autoradiography**
- This technique involves the use of radioactive isotopes to visualize DNA or RNA but is not primarily used for the separation of DNA fragments. Thus, this option is incorrect.

- **Option 2: Gel Electrophoresis**
- Gel electrophoresis is a widely used method for separating DNA fragments based on their size. It involves applying an electric field to a gel matrix, causing DNA fragments to migrate through the gel. Smaller fragments move faster than larger ones, allowing for separation. This option is correct.

- **Option 3: Microinjection**
- Microinjection is a technique used to introduce substances into cells using a fine glass pipette. It is not used for separating DNA fragments, making this option incorrect.

- **Option 4: Gel Filtration Chromatography**
- This technique is used for separating molecules based on their size in a solution but is not specifically used for DNA fragment separation. Therefore, this option is also incorrect.

3. **Conclusion:** After evaluating all the options, the correct technique for the separation of DNA fragments is **gel electrophoresis**.

**Final Answer:** The technique used for the separation of DNA fragments is **gel electrophoresis**.

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