What is detected by Southern blotting?

Southern blotting is a molecular biology technique specifically designed to detect specific sequences of DNA. This method involves the transfer of DNA fragments from an agarose gel onto a membrane, followed by hybridization with labeled probes that are complementary to the target DNA sequences. This allows for the identification of the presence and quantity of specific DNA sequences within a sample.

The reason that detection of DNA sequences is the focus of Southern blotting lies in its foundational principles. The technique hinges on the separation of DNA fragments based on size via gel electrophoresis, followed by their immobilization and hybridization with probes. This process is particularly useful in genetic research, diagnostic applications, and forensics, where identifying specific genes or mutations is important.

While other molecular biology techniques exist for detecting protein expression (such as Western blotting), RNA sequences (typically using Northern blotting or RT-PCR), and assessing cellular function, Southern blotting is exclusively tailored for DNA analysis, making it the correct choice in this context.