Appendices A Code and Data

B.1 The Genome and Non-Coding Regulation DNA, present in every cell, stores the complete set of instructions essential for life. It consists of a chain of nucleotides--adenine (A), thymine (T), guanine (G), and cytosine (C)--whose specific sequences encode functional elements. While genes, which code for proteins, are the most recognized of these elements, they constitute only a fraction of the genome. The complete DNA sequence of an organism is referred to as its genome. Within genes, coding sequences specify the amino acid composition of proteins.