It hasn't.

The gigantic international scheme to decode and figure out the order of every smidgen of DNA in a human cell has covered some serious distance since it began in earnest in 1990. But it's not there yet, even if CNN did devote pretty much the entire day's coverage to hosannas hailing imminent cures for cancer, for Alzheimer's disease, for heart disease, for pretty much everything that ails us. Wolf Blitzer declared that the announcement will affect your health "in the very near future."

It won't. The heads of the projects themselves mention that often. The public project's leader, Francis Collins of the National Human Genome Research Institute, cautions, "There is much left to be done." The private project's leader, Craig Venter of Celera Genomics Corp., said that Monday was "not a very important moment except that it's the beginning of what we can do with it."

Why all this modesty from the masters of an accomplishment that President Bill Clinton likens to Galileo's and Lewis and Clark's, that Tony Blair hails as "the first great technological triumph of the 21st century?" Because Collins and Venter know some things that CNN and its ilk aren't telling you.

For starters, nearly 66 percent of the data in the publicly funded project is in "draft" state, an acknowledgement that the DNA sequences are larded with mistakes. Collins likes to call the human genome sequence "our own instruction book." Well, your new instruction book is full of errors: factual errors and typographical errors. The original plan was to fact-check, spell check and proofread each of the millions of DNA sequences at least 10 or a dozen times to purge the goofs in analysis -- an inevitable consequence when the project comprises more than 3.1 billion pieces of information. But in the indecorous and very public race between the taxpayer-funded and the commercial HGPs, prudence was shed along with good manners. HGP officials, public and private, have settled, albeit temporarily, for half the amount of proofreading they know must eventually be done.

Your instruction book is also missing 15 percent of its pages. In addition to the errors, there are tens of thousands of gaps where the DNA has not been sequenced at all. Public and private scientists alike have waved away the gaps as inconsequential, but that's not entirely true. "It's impossible to answer whether the gaps are important," says Samuel Aparicio, a genome scientist at Cambridge University. "There will be genes that weren't known that will turn up in the gaps, and the gaps have to be closed. But the significance of having 90 percent of the sequence online is to help to show them."

And here's a human genome factlet that hardly anybody ever mentions. The projects have completely excluded a kind of highly condensed DNA called heterochromatin from sequencing. That's about 7 percent of the human genome, and there are probably some genes in it. Not many, but some.

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