The US president and the UK prime minister have hailed the rough draft of the entire human genetic code as "the most wondrous map ever produced by human kind".

This is the outstanding achievement not only of our lifetime but in terms of human history

Dr Michael Dexter, Wellcome Trust

Their words followed news conferences around the world on Monday at which scientists jointly announced that they had obtained a near-complete set of the biochemical instructions for human life.

The achievement is being called one of the most significant scientific landmarks of all time, comparable with the invention of the wheel or the splitting of the atom.

The genetic information will revolutionise medicine over the coming decades, giving us new tests and drugs for previously untreatable diseases. Some fear it could also lead to the emergence of a genetic underclass - people who have inherited faulty code.

The announcement also marked a coming together of publicly and privately funded researchers who have spent recent months in acrimonious rows, arguing over ownership and access to the data.

Medical revolution

To decipher the first draft, scientists had to read the three billion chemical "letters" strung out along the DNA spirals at the heart of nearly all our cells.

UK researchers, speaking at the first of many special ceremonies across several continents, said 97% of the human genome had now been mapped, with 85% of the code accurately sequenced.

Efforts would continue to fill in the gaps, they said, with a fully finished genome available within three years. Only 24% of the genome was currently in this "gold standard" format.

Researchers still have to search the finished data for the genes, the templates that cells use to make proteins. These are the large molecules that build and maintain the body, and which cause disease when they do not function properly.

Scientists hope that by knowing this information they will be able to develop a revolutionary new approach to medicine in which faulty genes can be corrected.

Scientific co-operation

President Bill Clinton and Prime Minister Tony Blair linked up via satellite to salute the work of the scientists.

 Click here to watch the satellite link-up

They said society had a duty to use the new information responsibly and for the benefit of all humankind.

Mr Clinton and Mr Blair saluted the efforts of the scientists

Mr Clinton was flanked at the White House by two of the major players in the race to unravel the "code of life": Dr Francis Collins, leader of the publicly funded Human Genome Project (HGP), and Dr Craig Venter, head of the private company Celera Genomics, which announced it too had produced a "first assembly" of the genetic code.

The two researchers have had major differences of opinion over the issues of scientific methodology and patents. But Mr Clinton heralded the end of these arguments by announcing a programme of co-operation between the two parties.

"The public and private efforts are committed to publishing their genomic data simultaneously later this year," said Mr Clinton. "They will then join together for an historic sequence analysis conference."

The big theme

Craig Venter's company used a different technique to obtain its "first assembly"

The rough draft has been completed years ahead of schedule thanks to the introduction of new robotic technology and the competition Celera gave the HGP when it started work in 1998.

"This is the outstanding achievement not only of our lifetime but in terms of human history," said Dr Michael Dexter, the director of the Wellcome Trust, which funded the UK part of the project.

"I say this because the human genome project, the reading of the book of mankind, does have the potential to impact on the lives of every person on this planet."

Dr John Sulston, director of the Sanger Centre, the main sequencing centre in the UK, said the announcement would be a huge philosophical step.

Dr John Sulston: More than 10 years of hard work

"We've now got to the point in human history where for the first time we are going to hold in our hands the set of instructions to make a human being," he told the BBC.

"That is an incredible philosophical step forward, and will change, I think, the way we think of ourselves."

Continuing the big theme, Dr Collins told the White House conference: "It is humbling for me and awe inspiring to realise that we have caught the first glimpse of our own instruction book, previously known only to God."