Question

Which one of the following is nucleic acid based detection test?

• A. ELISA
• B. RT-PCR
• C. Electron microscopy
• D. SDS-PAGE

Hint:

Molecular diagnostics targeting DNA or RNA (such as PCR, RT-PCR, and isothermal amplification) are nucleic acid-based tests.
Tests utilizing antibodies (such as ELISA and lateral flow strips) are protein-based serological assays.

Answer 1

The Correct Option is B

Diagnostic tests in plant pathology, veterinary science, and medicine are classified based on the target biomolecules they detect.
Tests can target the physical structure of a pathogen, its proteins (antigens), or its genetic material (nucleic acids).
Nucleic acid-based tests target the pathogen's DNA or RNA, providing high sensitivity and specificity.

Step 2: Detailed Explanation:
Let us analyze each of the diagnostic techniques provided in the options:
- ELISA (Enzyme-Linked Immunosorbent Assay): This is a serological, antibody-based technique.
It uses specific antibodies to detect the presence of target proteins or antigens of a pathogen in a sample.
Because it targets proteins rather than genetic material, it is not a nucleic acid-based test.
- RT-PCR (Reverse Transcription Polymerase Chain Reaction): This is a molecular diagnostic method.
It is designed to detect and amplify specific RNA sequences.
The enzyme reverse transcriptase first converts the target RNA into complementary DNA (cDNA), which is then amplified exponentially using DNA polymerase and sequence-specific primers.
Since it directly detects and copies specific genetic material (RNA), it is a nucleic acid-based test.
- Electron microscopy: This is a physical imaging technique.
It uses an electron beam to visualize the ultra-structure and morphology of viral particles or bacteria, rather than analyzing their chemical components.
- SDS-PAGE (Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis): This is a biochemical separation technique.
It denatures and separates proteins based on their molecular weight using an electric field, making it a protein-analytical method.

Step 3: Final Answer:
The only nucleic acid-based detection test among the choices is RT-PCR.