How many base pairs are in the human genome?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram of a DNA double helix showing its twisted ladder structure, with a close-up of the sugar-phosphate backbone, paired nitrogenous bases (adenine, thymine, cytosine, guanine), and labeled nucleotides and hydrogen bonds. — human genome The human genome is made up of approximately three billion base pairs of deoxyribonucleic acid (DNA). The bases of DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).

The human genome consists of approximately three billion base pairs of DNA.123

These base pairs are composed of four nitrogenous bases—adenine (A), thymine (T), guanine (G), and cytosine (C)—which form the structural foundation of the human genome. This vast sequence of genetic information, which was successfully mapped by the Human Genome Project, encodes between 20,000 and 25,000 genes and includes both coding and noncoding regions of DNA.132