Which of the following techniques serve the purpose of early diagnosils of diseases ?
(I) RELP
(II) PCR (III) ELISA

Options

A. I only
B. II & III only
C. I & III only
D. I & II & III

Answer

To determine which techniques serve the purpose of early diagnosis of diseases, let's analyze each option provided:

### Step 1: Understanding Early Diagnosis
Early diagnosis refers to identifying a disease at an initial stage before it progresses. This can help in timely intervention and treatment.

### Step 2: Evaluating RFLP (Restriction Fragment Length Polymorphism)
- **Definition**: RFLP is a technique used to identify variations in homologous DNA sequences by digesting DNA with restriction enzymes and separating the fragments by gel electrophoresis.
- **Application**: RFLP is primarily used in genetic mapping, paternity testing, and forensic analysis, but it is not typically used for the early diagnosis of diseases.
- **Conclusion**: RFLP does not serve the purpose of early diagnosis of diseases.

### Step 3: Evaluating PCR (Polymerase Chain Reaction)
- **Definition**: PCR is a widely used technique that amplifies specific DNA sequences, allowing for the detection of pathogens or genetic mutations.
- **Application**: PCR is particularly effective for diagnosing infectious diseases, such as COVID-19, by detecting the presence of viral RNA or DNA.
- **Conclusion**: PCR is a valuable tool for early diagnosis of diseases.

### Step 4: Evaluating ELISA (Enzyme-Linked Immunosorbent Assay)
- **Definition**: ELISA is a biochemical technique used to detect the presence of antibodies, antigens, hormones, or proteins in a sample.
- **Application**: ELISA is commonly used for diagnosing diseases by detecting specific antibodies or antigens, making it useful for early identification of conditions like HIV, certain cancers, and autoimmune diseases.
- **Conclusion**: ELISA serves the purpose of early diagnosis of diseases.

### Final Conclusion:
Based on the evaluations:
- **RFLP**: Not suitable for early diagnosis.
- **PCR**: Suitable for early diagnosis.
- **ELISA**: Suitable for early diagnosis.

Thus, the techniques that serve the purpose of early diagnosis of diseases are **(II) PCR and (III) ELISA**.