Hi everyone..as listed in the topics, i am here to present Northern blotting technique. Well, the northern blotting technique is similar to Southern blotting but the major difference is that the present technique deals with differentiating the gel fractionated segments of RNA. As said before, blotting is entrapment of nucleic acid on to Nitrocellulose or Nylon membrane. I've seen the NORTHERN BLOTTING in many books but a catchy explanation is given in the following website cited in the reference column. Procedure: 1. RNA is collected from biological samples- tissues, growing cells. 2. The fragments are separated based on their size (Molecular weights) on agarose gel. 3. The gel is blotted on to Nitrocellulose /Nylon membrane. Set of filter papers are placed in a buffer system with a labelled probe. Gel is placed on the papers. The Nitrocellulose membrane is placed above it. Lastly another set of filter papers are placed. 4. This labelled probe binds specifically with the complementary sequence of our fragments. The probe may be a ss DNA or RNA. During hybridization, the probe binds to its complementary sequence. 5. The membrane is washed to remove the unbounded probes. 6. The probes are then detected via autoradiography. Final result is the formation of thick bands upon development using X Rays. THIS BLOG IS FREE OF PLAGIARISM Ref: http://teachline.ls.huji.ac.il/72320/methods-tutorial/northern.html accessed on July 31st 2011.