Novel Application of Reversed Gel Electrophoresis: Reuse of DNA Molecular Weight Marker (100 bp DNA ladder)

100 bp DNA ladder is reused here for one time: The well corresponding to resolved DNA ladder is sealed with molten agarose. The resolved 100 bp DNA ladder is made to converge to a single band by reversing the electrode polarity or by facing the wells in gel towards the anode. The gel slice containing the DNA ladder is removed using scalpel or any other suitable device very carefully so that a thin rectangular gel piece containing the ladder is obtained. The gel slice or gel plug can be stored in water or in buffer at 4C in refrigerator. For reuse the gel plug is placed in a fresh well of agarose gel and the well is sealed with agarose. The test DNA samples are loaded in other wells. The electrophoresis again resolves DNA ladder from gel plug. The prior art internet search reveals commercially available low melting agarose gel plugs (eg., InCert agarose gel plugs sold by Lonza) containing large DNA fragments such as lambda DNA ladder that are used in Pulsed Field Gel Electrophoresis (PFGE). We have designed methods using reversed gel electrophoresis that favourably helps in reuse of resolved 100 bp DNA ladder.