Which method allows for the observation of DNA of interest in the Southern Blot process?

In the Southern Blot process, DNA of interest is observed primarily through the technique of autoradiography. This method involves creating a permanent record of DNA fragments that have been separated by gel electrophoresis and then transferred to a membrane.

In this process, DNA is hybridized with a labeled probe that is complementary to the target DNA sequences. The label can be radioactive or non-radioactive (such as biotin or digoxigenin). When using autoradiography, the membrane is exposed to photographic film or a phosphorimager, which captures the emitted signals from the radioactive probes, allowing for the visualization of the specific DNA fragments bound to the probes. This step is crucial for identifying the presence and quantity of specific DNA sequences within a sample.

Other methods listed, such as capillary action, microarray analysis, and colorimetric detection, serve different purposes or techniques in molecular biology and are not the primary means for detecting DNA in the Southern Blotting procedure. Capillary action helps in the movement of solutions across the membrane but does not visualize the DNA itself. Microarray analysis is a different technique used for simultaneous measurement of many DNA sequences, while colorimetric detection typically involves non-radioactive methods that are more common in other assays