Question

Probes are not used in

• A. Southern hybridization
• B. Northern hybridization
• C. RT-PCR
• D. Colony hybridization

Hint:

All biological hybridization techniques (Southern, Northern, Colony, and Western) require a labeled probe to locate a specific macromolecule within a complex mixture.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
A probe is a labeled single-stranded sequence of DNA or RNA used to detect complementary nucleic acids through sequence-specific hybridization.

Step 2: Detailed Explanation:
Southern hybridization requires labeled DNA probes to detect specific DNA sequences immobilized on a membrane.
Northern hybridization utilizes probes to identify specific RNA target sequences to determine gene expression levels.
Colony hybridization uses labeled probes to locate target genes within lysed bacterial colonies on nylon or nitrocellulose filters.
Standard RT-PCR (Reverse Transcription Polymerase Chain Reaction) converts RNA to cDNA, which is then amplified using sequence-specific primers.
The amplified PCR products are traditionally analyzed and confirmed by size separation on an agarose gel with an intercalating dye.
While real-time quantitative RT-PCR can use fluorescent probes, standard RT-PCR itself does not inherently require hybridization probes.
Therefore, standard RT-PCR relies primarily on primer extension rather than probe hybridization for target detection.

Step 3: Final Answer:
Hence, the correct option is (C).