Abstract
In this article we use Peyrard-Bishop-Dauxois model (PBD) to study the nonlinear oscillations of DNA nucleotides of extremely high amplitude (EHA) leading to unzipping of DNA chain in the context of the process of replication. We give arguments that the EHA mode is nothing but the resonance mode (RM). We launched an idea about how molecular mechano-chemical energy transduction can be the origin of the RM. We compared some parameters of the solitonic wave in DNA in resonant and non-resonant regime.