Which of the following is not an application of PCR ?

Options

A. ELISA
B. Diagnosis of pathogens
C. DNA fingerprinting
D. In palaeontology

Answer

To determine which of the following is not an application of PCR (Polymerase Chain Reaction), let's analyze each option provided:

1. **ELISA (Enzyme-Linked Immunosorbent Assay)**:
- ELISA is a diagnostic test used to detect the presence of antibodies or antigens in a sample. It is based on the interaction between antigens and antibodies, and it does not involve DNA amplification. Since PCR is specifically used for amplifying DNA, ELISA does not utilize PCR. Therefore, ELISA is **not an application of PCR**.

2. **Diagnosis of Pathogens**:
- PCR is widely used to diagnose various pathogens, including viruses and bacteria. For example, it can detect the presence of HIV by amplifying viral DNA integrated into the host's DNA. This application of PCR is crucial in medical diagnostics. Thus, this is an application of PCR.

3. **DNA Fingerprinting**:
- DNA fingerprinting is a technique used in forensic science to identify individuals based on their unique DNA profiles. PCR is essential in this process as it amplifies small amounts of DNA obtained from various sources (like hair, blood, etc.) to create a sufficient quantity for analysis. Therefore, DNA fingerprinting is also an application of PCR.

4. **Paleontology**:
- In paleontology, PCR can be used to amplify ancient DNA extracted from fossils, allowing scientists to study genetic material from extinct species. This application has made it easier for paleontologists to analyze and understand evolutionary relationships. Thus, paleontology is an application of PCR.

Based on the analysis above, the correct answer is that **ELISA is not an application of PCR**.

### Summary of Steps:
1. Identify the nature of each option.
2. Determine if PCR is involved in each application.
3. Conclude that ELISA does not involve PCR, while the others do.