Define a (molecular) probe and describe its use to identify a specific nucleic acid sequence.

### Molecular probes (DNA/RNA): Specific single-stranded sequences of DNA/RNA used to search for its complementary sequence in a sample genome (can be detected by hybridization with probe). The use of DNA probes permits microorganism identification, including pathogen detection, and their quantification when used in specific systems. Can for example be used to verify specific PCR products or "in situ hybridization" (ISH), for ex FISH, microarrays, northern & southern blot.

## Step1: Definition of Molecular Probe### A molecular probe is a specific single-stranded sequence of DNA or RNA. It is designed to search for its complementary sequence in a sample genome.## Step2: Detection Method### The probe can be detected by hybridization with the sample. This process involves the probe binding to its complementary sequence in the sample.## Step3: Applications in Microorganism Identification### Molecular probes are used in microorganism identification, including pathogen detection. They can also be used to quantify microorganisms in specific systems.## Step4: Verification of PCR Products### Probes can be used to verify specific PCR products, ensuring that the PCR has successfully amplified the desired sequence.## Step5: In Situ Hybridization (ISH)### Probes can be used in in situ hybridization (ISH) techniques, such as Fluorescence In Situ Hybridization (FISH), microarrays, northern blot, and southern blot.