Human genome

The entire genetic code or DNA of the species, home sapiens.

Human genome

Human genome

A genome is an organism's complete set of deoxyribonucleic acid (DNA), a chemical compound that contains the genetic instructions needed to develop and direct the activities of every organism.

Double strands

DNA molecules are made of two twisting, paired strands. Each strand is made of four chemical units, called nucleotide bases.

Human genome project

Nucleotides

The bases, also called nucleotides, are adenine (A), thymine (T), guanine (G) and cytosine (C). Bases on opposite strands pair specifically; an A always pairs with a T, and a C always with a G.

3 billion base pairs

The human genome contains approximately 3 billion of these base pairs, which reside in the 23 pairs of chromosomes within the nucleus of all our cells. Each chromosome contains hundreds to thousands of genes, which carry the instructions for making proteins. Each of the estimated 30,000 genes in the human genome makes an average of three proteins.

DNA sequencing

Sequencing means determining the exact order of the base pairs in a segment of DNA. Human chromosomes range in size from about 50,000,000 to 300,000,000 base pairs. Because the bases exist as pairs, and the identity of one of the bases in the pair determines the other member of the pair, scientists do not have to report both bases of the pair.

Human genome project

The Human Genome Project (HGP) was a worldwide collaboration that began on October 1, 1990 and completed in April 2003 sequencing the entire human genome.