what are the basic methods to isolate nucleic acids? Solution The basic methods used in DNA precipitation are, 1). DNA precipitation 2). Phenol-chloroform extraction During DNA extraction procedure, the DNA clumps out because it is not soluble in ethanol. DNA is soluble in water, but the sodium ions present in the extraction media neutralizes the negatively charged phosphate ions. Now, the DNA becomes less soluble and form aggregates or clump together upon the addition of ethanol. The yield increases with using cold ethanol because the DNA is even less soluble in cold ethanol..