Which of the techniques named below is considered a genotypic, molecular-based test?a) Gram stainb) Polymerase Chain Reaction (PCR)c) Microscopyd) Culture

To determine which technique is considered a genotypic, molecular-based test, let's analyze the options provided:

1. Gram Stain: This is a differential staining technique used to classify bacteria based on the characteristics of their cell walls. It is a phenotypic test, not molecular-based.

2. Polymerase Chain Reaction (PCR): This is a molecular biology technique used to amplify specific DNA sequences. PCR is indeed considered a genotypic technique since it involves the analysis of genetic material.

3. Microscopy: This technique involves examining specimens under a microscope to observe morphology and other physical traits. It is also a phenotypic test.

4. Culture: This involves growing microorganisms in controlled conditions to identify them based on their growth characteristics. It is considered a phenotypic method as well.

Final Answer

The technique that is considered a genotypic, molecular-based test is b) Polymerase Chain Reaction (PCR).