The race to decode the human genome may not be entirely over: the loser has come up with a new approach that may let him prevail in the end.
In 2003, a government-financed consortium of academic centers announced it had completed the human genome, fending off a determined challenge from the biologist J. Craig Venter. The consortium’s genome comprised just half the DNA contained in a normal cell, and the DNA used in the project came from a group of people from different racial and ethnic backgrounds.
But the loser in the race, Dr. Venter, could still have the last word. In a paper published today, his research team is announcing that it has decoded a new version of the human genome that some experts believe may be better than the consortium’s.
Called a full, or diploid genome, it consists of the DNA in both sets of chromosomes, one from each parent, and it is the normal genome possessed by almost all the body’s cells. And the genome the team has decoded belongs to just one person: Dr. Venter.
The new genome, Dr. Venter’s team reports, makes clear that the variation in the genetic programming carried by an individual is much greater than expected. In at least 44 percent of Dr. Venter’s genes, the copies inherited from his mother differ from those inherited from his father, according to the analysis published in Tuesday’s issue of PLoS Biology.
Huntington F. Willard, a geneticist at Duke University who has had early access to Dr. Venter’s genome sequence, said that the quality of the new genome was “exceptionally high” and that “until the next genome comes along this is the gold standard right now.”
Dr. Willard said it was “hugely better” than the consortium’s sequence, at least for his particular research interest.
“I don’t want to fan the fires but I like this, it’s a really good genome,” said Edward M. Rubin, a genome expert at the Lawrence Berkeley National Laboratory.
Dr. Venter’s race with the consortium began in 1998 when he spotted a quicker method of decoding the human genome. He tried to wrest this rich scientific prize from his academic rivals by co-founding a genome-decoding company called Celera. By June 2000, the two sides were neck and neck preparing a draft sequence of the genome. But in January 2002, Dr. Venter was abruptly fired as president of Celera. The consortium went on to claim victory when it announced its completion of the genome the next year.
But the consortium’s genome, though immensely useful to biologists, was full of gaps and only complete in the sense that it was the best that could be done with existing technology.
Dr. Venter has spent the last five years and an extra $10 million of his institute’s money in improving the draft genome he prepared at Celera. That genome was based mostly on his own DNA, and the new diploid version is entirely so. His critics may accuse him of an egocentricity of considerable dimension, but by analyzing his own genome he has sidestepped the problems of privacy and consent that could have arisen with other people’s DNA when he made the whole sequence publicly available, as he is doing now.
Like James Watson, the co-discoverer of DNA, whose genome is also being decoded, Dr. Venter believes strongly in making individual DNA sequences public to advance knowledge and hasten the era of personalized genomic medicine.
If other experts find that Dr. Venter’s genome is the best available, could it be said that he won the human genome race after all?
“There is this long history of Craig’s vanity, which for much of the scientific community is irritating,” Dr. Rubin said, declining to give a direct answer.
Asked the same question, Dr. Venter replied: “I’m not sure I’d want to be the one to say that, but we’re not through racing yet. I’ll let you know when we’ve stopped.”
James Shreeve, author of “The Genome War,” said, “I think he already believes he’s the true winner of the genome race for what he did at Celera,” noting that the consortium, too, believed it had won.
Though there are now novel technologies for decoding DNA very cheaply, Dr. Venter’s genome sequence could set a high bar for a long time. It was decoded with an old method, known as Sanger sequencing, that is expensive but analyzes stretches of DNA up to 800 units in length. The cheaper new technologies at present analyze pieces of DNA only 200 units or so long, and the shorter lengths are much harder to assemble into a complete genome.
Dr. Watson’s genome is being decoded with a next-generation machine developed by 454 Life Sciences. But the company’s researchers are putting the pieces in correct order by matching them to the consortium’s genome sequence rather than by doing an independent assembly.
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