There is an enormous amount of genomic data available for researcher in public databases. The genomic has the form of deoxyribonucleic acid (DNA) and plays a vital role in the function of every living cell. Hence, there is an essential need to understand the organization and the functionality of the DNA regions. Determining the key regions in DNA data is a very important problem for biologists. In order to address this important issue, various methods have been proposed from diverse disciplines such as biology, chemistry, physics, computer and electrical engineering. Signal processing theory is becoming increasingly very important in the study of genes in the field of bioinformatics. As the genomic information is digital, it can be represented in the form of numerical sequences that can be analyzed so that the results obtained are beneficial to humankind. In this paper, a quick review of molecular biology, DNA structure, followed by a brief review of signal processing methods for identifying protein-coding regions are presented.