SNPs are points where a single letter in a person's genome is different from what most people have. (Get an overview of human genetics.) Venter's genome has about 3.5 million SNPs.
Both Watson and Venter have hundreds of thousands of SNPs that are unique to themselves.
In addition to be faster, the new method is more comprehensive, Rothberg said, covering 3 percent of the genome that had either been skipped or couldn't be sequenced by older methods.
Rothberg noted that Watson's genome has about 200,000 larger chunks of DNA that were either added in or missing compared to the "average human genome" produced by the U.S. government's Human Genome Project.
"We now know that the Human Genome Project had made a mistake," Rothberg argued. "It underestimated the great diversity between individual people."
Genomes for the Masses
Although the analysis of Watson's genome was released today, the sequencing was actually done in the spring of 2007. The price has already dropped since then.
"Watson's genome cost a million dollars, and this year [a human genome] costs two hundred thousand," Rothberg said.
"Each year it becomes five times faster and five times cheaper," he said. "In six years, I'll give you a $2,000 genome."
454 Life Sciences was one of the first companies to register for the Archon X Prize for Genomics, a recently established award aimed at bringing personal genomes to the masses.
The first team to sequence a hundred whole human genomes in less than ten days for under $10,000 each will take home the $10-million prize.
Competition aside, the company's work on Watson's genome is "very important to convince people that next-generation sequencing is here to stay," said George Church of Harvard Medical School in Boston, Massachusetts.
But Church warns that the claims by companies of how much it costs them to sequence the human genome may not be reliable.
"The problem is none of these companies are documenting their prices," Church said. Even when the price is published in a journal, "this part isn't peer reviewed."
One way of proving that a price is real is if "you can offer it as a service," Church said. That's the approach of Knome, a company in Cambridge, Massachusetts, that Church co-founded.
If a company can't sequence genomes as cheaply as advertised, then in the long run "it will go broke," Church said.
Knome was the first to offer whole genome sequencing commercially, starting last winter. At their current price tag of $350,000, they've so far had two buyers.
But understanding all this genetic information is another matter.
Figuring out how genes are connected to various traits and diseases is "something we're all going to have to undertake as a society over the next ten years," study author Rothberg said.
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