Question

Which of the following technique is suitable for identifying mRNA molecule in a sample?

• A. Western blotting
• B. Northern blotting
• C. Southern blotting
• D. Eastern blotting

Hint:

Northern blotting is essential for detecting and studying RNA, including mRNA, in gene expression studies.

Answer 1

The Correct Option is B

Northern blotting separates RNA molecules by size using gel electrophoresis, transfers them onto a membrane, and then uses a labeled complementary probe to detect a specific RNA sequence, making it the standard technique for identifying mRNA in a sample. This is distinct from Western blotting (which detects proteins) and Southern blotting (which detects DNA), with the name "Northern" itself following the geographic-direction naming convention that distinguishes these related techniques.

Therefore, the correct answer is Northern blotting.

Answer 2

Another way to remember this is through the naming pattern used across these blotting techniques, each tied to the molecule it detects.

1. Western blotting: Tied to protein detection via antibody binding, this technique has nothing to do with nucleic acids.
2. Northern blotting: Following the same naming logic as Southern blotting but applied to RNA instead of DNA, this technique is specifically built to detect RNA molecules such as mRNA.
3. Southern blotting: Named after its inventor Edwin Southern, this technique detects DNA fragments, not RNA.
4. Eastern blotting: This term is used loosely for detecting protein modifications or lipids and is not the recognized method for mRNA detection.

Using the naming convention that parallels DNA-detecting Southern blotting, RNA detection is handled by Northern blotting.

Therefore, the correct answer is Northern blotting.