Which of the following is not an application of PCR (Polymerase Chain Reaction) ?

The correct answer is Purification of isolated protein.

Step-by-Step Explanation:

1. Understanding Polymerase Chain Reaction (PCR):
PCR is a molecular biology technique used to make millions to billions of copies of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it to an amount large enough to study in detail.

2. Analyzing the Options:
• Molecular diagnosis: PCR is widely used for molecular diagnosis to detect pathogens (like bacteria or viruses) by amplifying their specific DNA/RNA sequences.
• Gene amplification: This is the primary purpose of PCR, which is to amplify specific segments of DNA/genes.
• Detection of gene mutation: PCR is used to amplify specific gene regions, which can then be sequenced or analyzed to detect mutations associated with genetic diseases or cancers.
• Purification of isolated protein: PCR is a DNA-based enzymatic amplification process. It is not used for purifying proteins. Protein purification involves biochemical techniques such as chromatography (e.g., affinity chromatography, size-exclusion chromatography) or electrophoresis, which separate proteins based on their physical and chemical properties like size, charge, or binding affinity.

3. Conclusion:
Therefore, purification of isolated protein is not an application of PCR.