Dot Blots and Slot Blots,Nitrocellulose Membrane,Autoradiography,Labelled Probes,Gel Electrophoresis,Enzymes

www.molecular-plant-biotechnology.info

	Dot Blots and Slot Blots - Another variety of Southern or Northern blots is dot blots or slot blots. In dot blots, cloned or pure extracted DNAs to be tested are spotted adjacent to each other on a nitrocellulose membrane. DNA blots thus produced are immobilized and denatured so that they are bound on the membrane as single stranded DNA blots. The membrane is then hybridized with readioactively labelled probe (DNA or RNA). The dot representing sequence related to probe will light up by autoradiography.
The intensity of the dot will indicate the relative concentration of a sequence related to the probe in the DNA sample used for a particular dot. No steps involving digestion with enzyme, gel electrophoresis or transfer from gel to membrane are needed in this technique. Therefore, it is considered much more convenient, when no restriction sites are needed to be studied. Sometimes, an apparatus is used for placing spots on the membrane, through slots made in this equipment. The spots made thus are in the form of oblong slots rather than round blots. These slots are used just like dot blots and are described as slot blots.