Can a disease be detected before its symptoms appear? Explain the principle involved.
When the symptoms of the disease are not visible and the pathogen concentration is very low, then detection by conventional diagnostic tests is very difficult. However, detection is possible by the amplification of their nucleic ’ acid by the technique known as Polymerase Chain Reaction (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 and appropriate conditions.