Q.How is biotechnology helpful in molecular diagnosis?

Recombinant DNA technology provides highly sensitive molecular diagnostic tools — PCR and ELISA — that can detect a disease-causing agent at very low concentrations, well before traditional symptom-based diagnosis would be possible.

Early diagnosis of a disease is essential for successful treatment, but conventional methods of testing (serum/urine analysis) usually detect a pathogen or a disease marker only when its concentration is relatively high. Biotechnology-based molecular diagnostic techniques allow much earlier and more sensitive detection:

1. Recombinant DNA technology, PCR (Polymerase Chain Reaction), and ELISA (Enzyme-Linked Immunosorbent Assay) are used for early diagnosis of diseases even when the pathogen's concentration in the body is very low (undetectable by conventional methods).

2. PCR: This technique is used to detect the presence of pathogen (bacteria/virus) nucleic acid (DNA/RNA) in a patient's sample by specifically amplifying that pathogen's genetic sequence using specific primers. If the pathogen's DNA/RNA is present even in a very small amount, PCR can amplify it to a detectable level, allowing very early diagnosis — for example, in detecting HIV in AIDS patients well before antibodies appear, or in detecting mutations in genetic disorders and even in the identification of cancer-related genes.

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