Purification of DNA from agarose gels

James K. Polman, Louisiana State University
John M. Larkin, Louisiana State University

Abstract

We describe a rapid and easily reproducible modification of the "freeze-squeeze" method of separating DNA from agarose gels. Our method involves slicing out the agarose gel portion which contains the DNA of interest, freezing this gel slice at -20°C, then centrifuging the frozen slice in a filtration unit which contains a cellulose acetate filter. The agarose is retained on the filter and the filtrate contains the DNA. DNA purified in this manner could be completely digested with restriction endonucleases and completely ligated with DNA ligase, without further purification. The percentages of recovery for various sizes of linear and plasmid double-stranded DNA ranged from 57 to 69%. The procedure takes less than 30 minutes to perform. © 1989 Science & Technology Letters.