For which of the following is Polymerase Chain Reaction (PCR) used in molecular diagnosis?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → All of the above.
PCR (polymerase chain reaction) makes millions of copies of a chosen piece of DNA. Because of this, even a very small amount of DNA from a pathogen or a faulty gene can be amplified and detected. This makes PCR a tool of molecular diagnosis, that is, finding a disease early from its DNA.
Option (1) To detect HIV in suspected AIDS patients. — Correct statement, but it is only one of the correct points, so on its own it is not the answer. PCR is routinely used to detect HIV (human immunodeficiency virus) in suspected AIDS patients, even before symptoms appear.
Option (2) To detect mutations in the genes of suspected cancer patients. — Correct statement, but it is only one of the correct points, so on its own it is not the answer. PCR is also used to detect mutations in genes of suspected cancer patients.
Option (3) To diagnose many genetic disorders. — Correct statement, but it is only one of the correct points, so on its own it is not the answer. The book calls PCR a powerful technique to identify many other genetic disorders.
NCERT Extract:
Molecular Diagnosis – “… However, very low concentration of a bacteria or virus (at a time when the symptoms of the disease are not yet visible) can be detected by amplification of their nucleic acid by PCR. … PCR is now routinely used to detect HIV in suspected AIDS patients. It is being used to detect mutations in genes in suspected cancer patients too. It is a powerful techqnique to identify many other genetic disorders.”