Q. 20 Can a disease be detected before its symtoms appear? Explain the principle involved.
However, detection of a disease before the appearance of symptoms is possible by the amplification of victim's nucleic acid by PCR
The principle involved here is that a single DNA molecule can be copied endlessly in a test tube using primers, DNA polymerase enzyme and free nucleotides. The desired DNA of the pathogen is amplified by PCR from a limited amount of DNA template.