The DNA fragments separated on an agarose gel can be visualised after staining with

Options

A. Aniline blue
B. Acetocarmine
C. Ethidium bromide
D. Bromophenol blue

Answer

**Step-by-Step Solution:**

1. **Understanding Gel Electrophoresis**: The first step is to recognize that DNA fragments are separated using a technique called gel electrophoresis. This process involves applying an electric field to a gel matrix, which causes the negatively charged DNA fragments to migrate towards the positive electrode (anode).

2. **Role of Agarose Gel**: The agarose gel serves as a matrix that creates a sieving effect. Smaller DNA fragments move faster and further through the gel compared to larger fragments. This differential movement allows for the separation of DNA fragments based on size.

3. **Visualization of DNA Fragments**: After the separation of DNA fragments, they cannot be seen with the naked eye. Therefore, a staining method is required to visualize these fragments.

4. **Staining with Ethidium Bromide**: The common staining agent used for visualizing DNA fragments in agarose gel is ethidium bromide. This compound intercalates between the bases of DNA.

5. **Exposure to UV Light**: Once the DNA is stained with ethidium bromide, the gel is exposed to ultraviolet (UV) light. Ethidium bromide fluoresces under UV light, allowing the DNA fragments to be visualized.

6. **Observation of Results**: The DNA fragments will appear as bright orange bands on the gel when viewed under UV light, indicating their presence and allowing for analysis.

**Final Answer**: The DNA fragments separated on an agarose gel can be visualized after staining with **ethidium bromide**.

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