The human genome is the complete set of human genetic information, stored as deoxyribonucleic acid (DNA) sequences within the 23 chromosome pairs of the cell nucleus, and in a small DNA molecule within the mitochondrion. The haploid human genome (contained in egg and sperm cells) consists of three billion DNA base pairs. Genetic information is encoded as a sequence of nucleotides – guanine, adenine, thymine, and cytosine – recorded using the letters G, A, T, and C.
The genetic difference between humans and the chimpanzee genome is less than 5%. We are a great ape. In comparison, the genetic difference between individual humans is tiny – about 0.1%, on average. So while individual humans may look and act remarkably differently we are all very closely related, genetically.