[10] Elution of DNA from agarose gels after electrophoresis

This chapter discusses the elution of deoxyribonucleic acid (DNA) from agarose gels after electrophoresis. The studies of genome structure and function rely heavily on the isolation and analysis of the defined DNA fragments. Gel electrophoresis is a simple, high-resolution method of separating specific DNA fragments on the basis of size. Agarose gels at concentrations of 0.1–2.5% resolve DNA from 150–880,000 base pairs, whereas acrylamide gels, ranging from 3–20%, afford a good resolution of fragments in the size range of 10–2,000 base pairs. The chapter describes three new or revised methods for the recovery of DNA from agarose gels. The evaluation is based on the simplicity, speed, yield, and amenability of the purified DNA. The first method involves the electroelution of DNA into slots. The second method involves the electroelution of DNA onto dialysis membranes. The third method describes the process of dissolving gel slices in perchlorate solution.