Monday, September 19, 2005

Southern exposure

Sir Edwin Southern has won this year's Lasker Award for his invention of a DNA blotting method. Southern's original idea is incredibly cool- you could analyze the fragmentation pattern of a complex mixture of DNA by using a "probe," which just consists of a short radioactively labelled fragment. The probe will only stick to its matching (complementary) sequence, and all other sequences stay blank. Using this simple idea and multiple probes, you can detect many different genetic changes, ranging in size from chromosomal rearrangements to loss of a single restriction site.

The method has proved so versatile that it has been adopted for RNA ("northern blot," a pun on Southern's last name), and then to protein ("western blot") and even to protein-protein interactions ( "far western" ). I am not aware of an eastern blot.

Southern later became an early advocate of microarray hybridization , which uses analagous techniques to a Southern blot.

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