dna extraction method: Using this method dna or rna can be extracted out of polyacrilamide gels. The portion of the gel containing the dna / rna of interest is excised and placed in a dialysis tube containing buffer solution. The bag is then electrophoresed causing the DNA/RNA to migrate out of the gel but does not leave the bag. It remains suspended in the buffer. The dna fragment is then recovered from the buffer and purified. This is done via phenol/chloroform extraction method followed by precipitation.