international scientific effort to map all of the genes on the 23 pairs of human chromosomes and, to sequence the 3.1 billion DNA base pairs that make up the chromosomes (see nucleic acid). Begun in 1990 with the goal of enabling scientists to understand the basis of genetic diseases and to gain insight into human evolution, the project was largely completed in 2000 when 85% of the human genome was decoded, and ended in 2003 with 99% decoded. In the process, scientists identified genes for cystic fibrosis, neurofibromatosis, Huntington's disease, and an inherited form of breast cancer. In addition, the project decoded the genome of the bacterium E. coli, a fruit fly, and a nematode worm (see phylum Nematoda), in order to study genetic similarities among species, and a mouse genome was also decoded.

The Human Genome Project involved laboratories in the United States, France, Great Britain, Germany, and Japan. It was financed in the United States by the National Institutes of Health (and, to a lesser degree, by the Department of Energy) and in Great Britain by the Wellcome Trust of London. A comparable project using new DNA (genetic material) sequencing machines was begun as a private industry venture in the United States in 1998, with a stated goal of completing the mapping of the genome in three years.

Early in 2001 scientists from both teams jointly announced the "completion" of the mapping of the human genome, indicating that they had identified an estimated 30,000 genes (instead of the expected 100,000), constituting just 1% of the total human DNA. Subsequent comparison of the two teams' data has indicated that, because of differences in the genes identified by the teams, there may in fact be as many as 40,000 human genes. Other experts, however, believe that final total of identifiable human genes will be significantly lower than 30,000.

See studies by J. Sulston and G. Ferry (2003) and J. Shreeve (2004).

The Columbia Encyclopedia, Sixth Edition Copyright© 2004, Columbia University Press. Licensed from Lernout & Hauspie Speech Products N.V. All rights reserved.

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