Generalized tube model of biased reptation for DNA-gel electrophoresis

We present a generalized tube model for the theoretical analysis of the reptational motion of DNA in gel electrophoresis. The generalized model incorporates effects of molecular fluctuations and is capable of explaining some main features observed in electrophoresis experiments involving periodic inversions of the external electric field. These features may be attributed to a delicate interplay between the internal motion and the center of mass motion of the DNA molecules under pulsed field conditions.