Human Genome Project

Between 1990 and 2003, scientists in several countries worked together to read, letter by letter, the roughly three billion chemical units of human DNA and to locate the genes they contain. Led and largely funded by the United States, with major contributions from Britain and laboratories in Japan, France, Germany and China, it was the largest collaborative project in the history of biology. It was declared complete on 14 April 2003, two years ahead of schedule, although the last difficult stretches of the genome were only filled in some two decades later.

Methods for reading DNA were developed in 1977 by Walter Gilbert, Frederick Sanger and Paul Berg, among others. In the mid-1980s several scientists independently proposed sequencing an entire human genome: Robert Sinsheimer held a workshop at Santa Cruz in May 1985, Charles DeLisi of the US Department of Energy organised a workshop at Santa Fe in March 1986, and the biologist Renato Dulbecco argued for the idea in the journal Science. James Watson, co-discoverer of the structure of DNA in the 1950s, held a further meeting at Cold Spring Harbor. DeLisi's efforts inside the Department of Energy led to the first funding, which Congress expanded from the late 1980s.

In 1990 the Department of Energy and the National Institutes of Health formally launched the project, budgeted at about 3 billion dollars and expected to take 15 years. Watson led the NIH genome programme until Francis Collins succeeded him in 1993. Most of the sequencing was done at twenty centres in six countries, grouped in the International Human Genome Sequencing Consortium; Britain's Wellcome Trust was a major funder. The DNA was cut into pieces of about 150,000 base pairs, copied in bacteria, sequenced and pieced back together. Because samples came from a few anonymous donors, the resulting reference genome is a composite rather than any one person's DNA. From the start, a share of the budget went to studying the ethical, legal and social questions raised by the work, such as fears of genetic discrimination by employers and insurers.

In 1998 the American scientist Craig Venter and his company Celera Genomics launched a private rival, costing about 300 million dollars and using a faster "whole genome shotgun" method. Celera sought patent rights on some genes and planned to restrict the use of its data, whereas the public project released its results daily. The public consortium put its first working draft online on 7 July 2000. On 26 June 2000 US President Bill Clinton and British Prime Minister Tony Blair had jointly announced the completion of a rough draft, and both groups published their drafts in February 2001.

The project's stated aim was the gene-rich euchromatic part of the genome, about 92 per cent of the whole, and this was declared finished in April 2003. The project cost less than planned, about 2.7 billion dollars. Its results were placed in public databases such as GenBank, free for anyone to use. Early findings suggested that humans have roughly 22,300 protein-coding genes, an estimate later revised down to around 19,000 to 20,000, far fewer than the 80,000 or more once assumed.

Repetitive regions near the centres and tips of chromosomes resisted the technology of the time. Using newer long-read methods, the Telomere-to-Telomere consortium published a complete sequence of all chromosomes except the Y in 2022, and the Y chromosome followed in August 2023. In 2024 a journalistic investigation reported that about three-quarters of the reference genome came from a single donor, despite consent forms promising no more than 10 per cent from any one person.

Our 1994 and 2000 maps show the main participating countries, among them the United States, the United Kingdom, Japan, France and China.