Northern blotting:

Northern blotting follows much the similar procedure as Southern blotting except in which the sample analyzed through gel electrophoresis and then bound to the filter is RNA not DNA. Thus the method detects RNA molecules which are complementary to the DNA probe if cellular RNA is electrophoresed for instance, a DNA probe for a specific mRNA could be used to detect whether which mRNA was present in the template. The migration distance of the RNA in the gel would also allow estimation of its size. Note down that Southern blotting for DNA obtained for RNA was devised later its name after its inventor E. Southern the name Northern blotting and is a geographical pun!