Rapid and inexpensive recovery method of DNA fragments from agarose and polyacrylamide gels by a cotton-wool column tube.

We developed a rapid, convenient, simple, and inexpensive method for isolating pure DNA from agarose and polyacrylamide gels using cotton wool tubes. DNA fragments ranging in size from 193-23,130 bp can be easily recovered within 2 hours by centrifugation through cotton wool from gel slices. The recovery rate of this method is 35% to 50%, when estimated for isolation of lambda DNA-HindIII fragments. We have also recovered 700-bp polymerase chain reaction (PCR) products using cotton wool tubes from electrophoresis on both a 0.8% agarose gel and a 6% polyacrylamide gel, in which satisfactory yields of more than 50% were obtained. The DNA thus recovered in this way is biologically active and can be used as a substrate for further experimental procedures without additional purification steps.