Genomic Signal Processing is an emerging interdisciplinary area. The problem of Identifying Protein Coding Regions in DNA is addressed using signal processing techniques in this paper. DNA can be thought as a string formed from the alphabet set script A = {A, C, G, T}. It is found that, in protein coding regions the symbols have periodicity of 3 [1], which can be used as a cue to identify the protein coding regions using signal processing techniques. This is possible only if the symbol sequences are mapped to numbers. In this paper a new lower dimensional mapping is proposed which reduces the computational complexity by half, producing results nearly equal to those produced by a higher dimensional mapping. ©2007 IEEE.