The Human Genome Project (HGP) was the international, collaborative research program whose goal was the complete mapping and understanding of all the genes of human beings. All our genes together are known as our “genome.”

The HGP has revealed that there are probably about 20,500 human genes. This ultimate product of the HGP has given the world a resource of detailed information about the structure, organization and function of the complete set of human genes. This information can be thought of as the basic set of inheritable “instructions” for the development and function of a human being.

The International Human Genome Sequencing Consortium published the first draft of the human genome in the journal Nature in February 2001 with the sequence of the entire genome’s three billion base pairs some 90 percent complete. More than 2,800 researchers who took part in the consortium shared authorship.A startling finding of this first draft was that the number of human genes appeared to be significantly fewer than previous estimates, which ranged from 50,000 genes to as many as 140,000. The full sequence was completed and published in April 2003.

Although scientists have performed many of these tasks and experiments for decades, the Human Genome Project is unique and remarkable for the enormity of its effort. The human genome contains 3 billion DNA building blocks (i.e., nucleotides), enough to fill approximately one thousand 1,000-page telephone books if each nucleotide is represented by one letter. Given the size of the human genome, researchers must develop new methods for DNA analysis that can process large amounts of information quickly, cost-effectively, and accurately. These techniques will characterize DNA for family studies of disease, create genomic maps, determine the nucleotide sequence of genes and other large DNA fragments, identify genes, and enable extensive computer manipulations of genetic data.