In the context of gene expression analysis, which blotting technique is preferred to study mRNA levels?

The preferred blotting technique to study mRNA levels is the Northern Blot. This technique is specifically designed to detect and quantify RNA transcripts, allowing researchers to analyze gene expression by measuring the amount of specific mRNA in a sample.

During a Northern Blot, RNA is extracted from cells or tissues and then separated by size through gel electrophoresis. The RNA is subsequently transferred to a membrane and hybridized with a labeled probe complementary to the target mRNA. The presence and intensity of the signal from the probe indicate the abundance of the specific mRNA, providing insights into gene expression levels.

In contrast, other techniques mentioned serve different purposes: the Southern Blot is used for DNA analysis, primarily to detect specific DNA sequences; the Western Blot is focused on proteins, allowing for the detection and quantification of specific proteins in a sample; and PCR amplification is a method for amplifying specific segments of DNA, not RNA. Each of these techniques is suited to its respective type of molecule, making the Northern Blot the appropriate choice for mRNA study.