DNA polymerase uses DNA template to catalyse the polymerization of deoxynucleotides and hence it is called DNA - dependent. When a new strand of DNA is being processed, this enzyme moves along to hasten the speed of polymerization. While doing so, it "proof reads" the strand being formed. By doing so, it helps In speeding up the process. Hence, its nature can be said as dual, i.e. of reading the template and then proof reading the new strand.