06+Southern+Blotting

Southern Blotting

Describe it: A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. The amount of DNA needed for this technique is dependent on the size and specific activity of the probe. Short probes tend to be more specific. The key to this method it hydrolization. Hydrolization is chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism.

Analyze it: Southern blotting was named after Edward M. Southern who developed this procedure. This is how southern blotting works. First the DNA is digested with a restriction enzyme and separated by gel electrophoresis. Then the DNA is transferred to a membrane which is a sheet of special blotting paper. The DNA fragments retain the same pattern of separation they had on the gel. After that the blot is incubated with many copies of a probe which is single-stranded DNA. This probe will form base pairs with its complementary DNA sequence and bind to form a double-stranded DNA molecule. The probe cannot be seen but it is either radioactive or has an enzyme bound to it. Finally the location of the probe is revealed by incubating it with a colorless substrate that the attached enzyme converts to a colored product that can be seen or gives off light which will expose X-ray film. If the probe was labeled with radioactivity, it can expose X-ray film directly.

Apply it: Southern blotting is designed to locate a particular sequence of DNA within a complex mixture. For example, Southern Blotting could be used to locate a particular gene within an entire genome. Southern blotting is also used to detect the presence of a particular piece of DNA in a sample. The DNA detected can be a single gene, or it can be part of a larger piece of DNA such as a viral genome. Gene discovery and mapping studies to monitor gene incorporation and to assess evolutionary relationships among organisms are some other ways that southern blotting is used.

Synthesize: Southern Blotting reminds me of rubber stamping a card or something like that. In southern blotting you "stamp" the DNA from one thing to the next a couple times and when stamping you stamp that ink onto the stamp and then onto paper.

Argument: I think that southern blotting is a good thing because it helps in many ways. It helps people find a specific DNA sequence in a DNA sample so that they can figure out many things.



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Sources: microscopeblog.com book askabiologist.asu.edu/southern-blotting