An optimized freeze-squeeze method for the recovery of DNA fragments from agarose gels

A procedure for quick and simple elution of DNA from agarose gels is presented. After electrophoresis, bands of interest are cut out of the gel and the slices are equilibrated in a neutral salt buffer. The slices are then frozen and centrifuged through a filtration assembly whereby the DNA-containing buffer is squeezed out. The method is simple, quick, and suitable for the safe handling of small amounts of DNA (less than 1 microgram). The isolated DNA is susceptible to any enzymatic reaction and also to chemical sequencing. The method is most useful for rapid preparation of specifically end-labeled DNA fragments (e.g., for sequencing), but may also be utilized for any other preparative applications.