DYNAMICS OF DNA-MOLECULES IN AGAROSE-GEL UNDER SINUSOIDAL ELECTRIC-FIELDS

The dynamics of DNA molecules in agarose gel has been studied by measu ring the birefringence in sine wave electric fields. It was found that the birefringence is the sum of a direct current (dc) component and s everal harmonics of the field frequency. A detailed study of these com ponents was performed. It was found that the dynamics of DNA molecules under these conditions can be explained by a W conformation which is not detected under de electric fields. The variation of the field freq uency gives several relaxation modes in the birefringence signal, refl ecting the known dynamic behavior of DNA molecules found in the reptat ion with elongation of the tube length regime.