Which test is specifically used to detect known DNA sequences characteristic for a pathogen?

The technique used to detect known DNA sequences characteristic for a pathogen is Polymerase Chain Reaction (PCR). PCR is a powerful molecular biology method that amplifies specific DNA segments, allowing for the detection of even minute quantities of DNA present in a sample. This capability makes PCR particularly effective for identifying bacterial, viral, or other pathogen DNA within clinical samples.

During PCR, specific primers that are complementary to the sequences of interest are designed to bind to the target DNA. When heated, the double-stranded DNA is denatured into single strands, and upon cooling, the primers anneal to the target sequences. A DNA polymerase enzyme then synthesizes new strands of DNA, exponentially increasing the amount of the targeted DNA when cycles of heating and cooling are repeated. This amplification process enables the detection of pathogens based on their unique genetic material.

In contrast, the other techniques listed have different applications. Enzyme-Linked Immunosorbent Assay (ELISA) is used for detecting antigens or antibodies in a sample, primarily to measure the immune response rather than to identify specific DNA sequences. Western Blot is a method for detecting specific proteins in a sample and is not designed for DNA detection. Flow Cytometry is a technique used to analyze the physical and chemical