Which one of the following is NOT a method of molecular diagnosis for early detection of a disease?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → RNAi
Option (1) rDNA technology — A method. NCERT names recombinant DNA technology among the techniques that serve early diagnosis.
Option (2) RNAi — Not a method. RNA interference is used to make pest-resistant plants, not to detect disease.
Option (3) PCR — A method. PCR (Polymerase Chain Reaction) amplifies the nucleic acid of a pathogen, so even a very low amount can be detected.
Option (4) ELISA — A method. ELISA (Enzyme Linked Immuno-sorbent Assay) detects the antigens of a pathogen or the antibodies made against it.
NCERT Extract:
Molecular Diagnosis – “… You know that for effective treatment of a disease, early diagnosis and understanding its pathophysiology is very important. Using conventional methods of diagnosis (serum and urine analysis, etc.) early detection is not possible. Recombinant DNA technology, Polymerase Chain Reaction (PCR) and Enzyme Linked Immuno-sorbent Assay (ELISA) are some of the techniques that serve the purpose of early diagnosis.”
Biotechnological Applications in Agriculture – “… RNAi takes place in all eukaryotic organisms as a method of cellular defense.”