Background The schematic for every living organism is stored in long molecules known as chromosomes made of a substance known as DNA (deoxyribonucleic acid. Each cell in an organism has a complete copy of its DNA, also known as its genomewhich is conveniently modeled as a sequence of symbols (alternately referred to as nucleotides or bases) in the DNA alphabet {A,C,T,G}. In humans, and most mam...