Gene tycoon has 3bn letters of DNA - but can't read them

Last week's 'milestone' in genetic research announced by Celera was largely hype, according to rival scientists

Craig Venter's announcement last week that he had sequenced the entire genetic recipe of a human being was billed as a milestone. But by the weekend, it was being ridiculed as overblown "hype" by his rivals in the official human genome project.

Mr Venter, president and chief executive officer of Celera Genomics, saw his company's share price soar after he told the US Congress that he had finished reading the three billion "letters" that make up the complete DNA code of man.

"This is the key milestone," said Mr Venter, a Vietnam veteran turned medical maverick. "Now that we have completed the sequencing of one human being's genome, we will turn our computational power to the task of ordering the human genome."

What Mr Venter meant by his elliptical statement is that, although his computerised "gene machines" have sequenced all the three billion letters - technically known as base pairs - he cannot yet tell you what they spell.

Tim Hubbard, head of human genome sequencing at the Sanger Centre in Cambridge, part of the international operation racing against Celera, suspected that Mr Venter's "milestone" announcement was aimed more at his shareholders than scientists.

"It doesn't mean anything. He's got fragments of DNA sequences but he has not yet assembled them into anything meaningful," Dr Hubbard said. "It's like taking a copy of the Encyclopaedia Britannica and shredding it. You might be able to read fragments of it but it won't mean very much."

The rivalry between Celera, a private organisation set up to make a profit out of decoding the 100,000 or so genes on the 23 pairs of human chromosomes, and the publicly funded Human Genome Project centres on who will control the rights to exploit the huge database of genetic information that could transform medicine in the 21st century. Knowing the sequence of DNA letters in each of the genes will open the way to new tests for genetic disorders, not just for the obvious ones such as cystic fibrosis, but the more complicated inherited predispositions behind the common killers, from cancer to heart disease.

Unravelling the human genome will enable pharmaceutical companies to design new drugs, some of which could be tailor-made for the needs of individual patients carrying a certain set of genes.

It also raises the prospect of the genetic engineering of "designer babies", ridding a family of an inherited curse or even modifying a perceived physical or mental deficiency.

Mr Venter's technique is radically different to the more methodical and slower approach of the Human Genome Project. Although they both use the same gene machines - robotic chemistry sets for reading the sequence of each of the four DNA base pairs - Mr Venter does it in a "shotgun" manner.

Imagine the vast amount of information locked up in our chromosomes as individual bricks in a multistorey building. The Human Genome Project's approach to understanding where each brick is placed is to remove them one by one. Mr Venter's approach is to blow up the building and try to work out what goes where from the fragments of rubble left behind.

Celera has already had some success with this fast and dirty method, having decoded the entire genomes of simpler organisms such as microbes and a fruit-fly. The official project, meanwhile, has fully decoded the entire sequence of human chromosome number 22, and is two thirds of the way through finishing the rest of the human genome.

But whereas the 16 collaborating institutes behind the Human Genome Project have vowed to make their discoveries publicly available and free, Celera wants to build up a database which it will charge commercial organisations to use.

Mr Venter has denied that he intends to patent individual DNA sequences, but his critics fear that his threat to impose commercial control over human genes will ultimately stifle research.

"The patenting law is a mess, and it's different between America and here. You can't patent the DNA but with a clever lawyer you can find a way of tying up a gene," Dr Hubbard said.

This confusion over what can and cannot be patented in terms of DNA technology, currently under review by the US Patent Office, is partly behind the unprecedented joint statement issued last month by Bill Clinton and Tony Blair, who reaffirmed their governments' declared positions that access to the human genome should be freely available.

When the Blair-Clinton statement was announced, the share price of Celera fell through the floor. However, it bounced back again this week when Wall Street realised that there might still be fortunes to be made from the encyclopaedia of information locked away in human chromosomes.

However, some experts question whether Celera will ever have real control over the genome. Within the next few weeks another "milestone" will be announced, this time by the Human Genome Project, which will say it has completed the first "rough draft" of the book of man.

This time, however, it will have page numbers to guide readers to where each piece of new information should go. That is something Mr Venter is still trying to figure out.