An individual’s genome is the entire set of their genetic material (DNA) and includes all their DNA both within and between genes. All of these regions of the genome are composed of four nucleotides: adenine (A), cytosine (C), guanine (G), and thymine (T). Whole genome sequencing is the process of determining the order of these nucleotides in an individual’s DNA. It allows the identification of differences in the DNA (genetic variants) between the individual and the reference genome.