Dielectric studies of intermolecular interactions in native DNA.

The concentration dependence of the high frequency dielectric dispersion exhibited by solutions of DNA and the sensitivity of this to the ionic strength of the solution are described. Dielectric data obtained are consistent with a model involving the fluctuation of counterions along short segments of the DNA chain. The concentration and ion strength dependencies are discussed in terms of intermolecular interactions which are considered responsible for the existence of structure in DNA solutions.