Identify the the mismatch from the following

Options

A. Precipitation of DNA-Chilled ethanol
B. Separation of DNA fragments -Gel electro-phoresis
C. Staining of DNA-Ethidium bromide
D. Multiple copies of DNA fragments-ultra centrifugation

Answer

To identify the mismatch from the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Option 1: Precipitation of DNA with chilled ethanol**
- This statement is true. Ethanol precipitation is a common technique used to concentrate and desalting nucleic acids (DNA or RNA). Typically, 70% chilled ethanol is used for this process.

2. **Option 2: Separation of DNA fragments by gel electrophoresis**
- This statement is also true. Gel electrophoresis is a widely used method for separating DNA fragments based on their size. The DNA fragments are placed in agarose gel, and when an electric current is applied, they migrate towards the anode, separating according to their molecular weight.

3. **Option 3: Staining of DNA in ethidium bromide**
- This statement is correct as well. Ethidium bromide is a common stain used for visualizing DNA and RNA. It intercalates between the base pairs of the DNA double helix and fluoresces under UV light, allowing for the visualization of the nucleic acids.

4. **Option 4: Multiple copies of DNA fragments by ultracentrifugation**
- This statement is incorrect. Ultracentrifugation is not the method used to create multiple copies of DNA fragments. The correct technique for amplifying DNA fragments is the Polymerase Chain Reaction (PCR), not ultracentrifugation.

### Conclusion:
The mismatch is found in **Option 4**, which incorrectly states that ultracentrifugation is used for creating multiple copies of DNA fragments. The correct method for this purpose is PCR.

### Final Answer:
**Mismatch: Option 4 - Multiple copies of DNA fragments by ultracentrifugation**

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