Molecule-based transistors have attracted much attention due to their exclusive properties. Creation of a molecular transistor as well as engineering its structure have become one of the greatest aims of scientists. We have focused on the environmental dependent behavior of a DNA-templated transistor. Using the statistical distribution of the energy levels, we were able to distinguish the delocalized states of charge carriers and the transition between the localized and delocalized behaviors. On the other hand, we can determine the stability conditions of our quantum dynamical system. The results are verified by the inverse participation ratio method. Therefore, the most appropriate parameters for designing the DNA transistor are chosen. The DNA sequence is an important factor for its transport properties, but the results have shown that in the presence of the bath, the bath parameters are important, too. As is shown, it is possible that via the adjustment of bath parameters, one can design a conductivity channel for all nucleotide contents. Thus, one can engineer a DNA based transistor simply through the setting of only one parameter.