Question

Which technique CANNOT be used to analyze gene expression?

A) Western blotting
B) Northern blotting
C) Southern blotting
D) Reverse transcription PCR

Answer 1

C. Southern blotting cannot be used to analyze gene expression, as it is a method for detecting specific DNA sequences within a DNA sample.

Step-by-step explanation:

The technique that cannot be used to analyze gene expression is C) Southern blotting. Southern blotting is a method used to detect specific DNA sequences within a DNA sample, not to measure gene expression, which involves mRNA. To analyze gene expression, one could use techniques such as:

• Western blotting, which is used to detect proteins that are expressed as a result of gene expression after the translational stage.
• Northern blotting, which is used directly to detect the presence and amount of mRNA in a sample.
• Reverse transcription PCR (RT-PCR) which converts RNA into DNA (cDNA) and then amplifies specific cDNA targets indicating gene expression levels.

These techniques are crucial in understanding the functional elements of the genome and how genes are regulated within an organism. While Southern blotting is an essential method in molecular biology, its application is different and it is not used to measure gene expression.