Segments of the DNA are calculated with the Peyrard-Bishop-Holstein model. The results show that the two controversial charge transport mechanisms, hopping and tunneling, are not consummate to depict its behaviors along the DNA chains composed of RnRm'R-p '', in which the polaron will annihilate gradually and meanwhile new one will be created at some new ones in the presence of an electric field. We speculate the phenomenon can be explained by the collective vibration of the lattices and the two intensity couplings: one is between lattices and a charge; the other is hydrogen bond interaction between complementary bases. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.