Genome sequencing is the process of finding out the order of DNA nucleotides, or bases, in a genome—the order of adenines, cytosines, Guanines, and Thyamines that make up an organism's DNA. The human genome is made up of over 3 billion of these genetic letters. Now-a-days, DNA sequencing on a large scale is frequently done by high-tech machines. These machines interpret a sequence of DNA bases.