[Theory of DNA compactization in a polymer solution]

A theory of DNA compactization is suggested. It is based on the concept about compact DNA globule as a polymeric one. The polymeric solution is considered as a strongly fluctuating system, and the double helical DNA as a rigid unifilar homopolymer. The globule is shown to appear in a diluted polymeric solution. The character of relative phase transition is analysed. With an increase of polymeric solution concentration the size of the DNA globule should decrease and the optic activity increase. Conditions are indicated under which the decompactization of DNA takes place at high concentrations of polymeric solution. This event is accompanied by an abrupt increase of DNA size and a decrease of optical activity.