The final version of the entire human genome sequence was unveiled last week by the International Human Genome Sequencing Consortium, more than two years ahead of schedule. Since the 'rough draft' was published in February 2001, researchers have been proof-reading the sequence, and filling in most of the gaps. A paper outlining the future of human genome research is to be published in Nature this week, to coincide with the 50th anniversary of the publication of the DNA double helix.

The finished sequence of three billion DNA chemical 'letters', or base-pairs, is highly accurate, with less than one error per 100,000 base-pairs. Researchers have also closed over 99 per cent of the gaps present in the draft sequence, though 400 technically intractable gaps remain. Formally begun in 1990, the work was carried out at 20 sequencing centres in China, France, Germany, Japan, the UK and the US. All made their data freely available via the Internet as soon as it was produced. 'The working draft allowed researchers to kick-start a number of biomedical projects' said Jane Rogers, head of genome sequencing at the UK's Wellcome Trust Sanger Institute, which carried out a third of the work. 'Now they have a highly polished end product that will help them even more'. Celera Genomics, the US biotech firm that published its own draft human genome sequence in 2001, did not go on to produce a final version.

Research projects are now underway to find out what all of the genes encoded within the human genome do, the function of the proteins they make and how genetic variation affects human health. 'The completion of the Human Genome Project should not be viewed as an end in itself' stressed Francis Collins, director of the US National Human Genome Research Institute. 'Rather, it marks the start of an exciting new era - the era of the genome in medicine and health' he said.