| Tom Siegfried: Genetic book speaks volumes about humankind 02/26/2001 By / The Dallas Morning News SAN FRANCISCO – Translating messages from an alien civilization, Carl Sagan once said, would be like breaking the Egyptian hieroglyphic code.
In chapter 12 of Cosmos, the book accompanying the TV series, Sagan imagined that such alien messages might arrive via radio signals encoding an "Encyclopaedia Galactica," a catalog of all the intelligent civilizations inhabiting the cosmos.
Sagan fans still await the alien transmissions. But biologists have now received their version of a similar wish, the catalog of instructions for building human bodies.
Let's call it Encylopedia Genetica.
Like Champollion upon seeing the Rosetta Stone, Francis Collins can hardly contain his excitement about getting a glimpse of the new encyclopedia.
"This is the most exhilarating moment in my scientific career," he said in San Francisco this month at the annual meeting of the American Association for the Advancement of Science.
Dr. Collins, head of the government's effort to catalog all the genetic information contained in human cells, says the gene encyclopedia is three books in one.
It's a history book – the record of the evolution of human life. It's a parts manual, listing the blueprints for all the molecules that make the body's cells and make them work. It's a textbook for doctors, a guide to identifying the misprints in some genes that translate into medical maladies.
Days before Dr. Collins spoke in San Francisco, his team and a privately funded project had released their first analyses of the new gene encyclopedia. Since then Dr. Collins has been busy explaining its significance to anybody who will listen. He related one attempt to explain it all to a high school student.
"I get it," the kid responded. "You wrote a book report."
Actually, it was a rough-draft book report about a rough draft of a book. Encyclopedia Genetica is not really finished yet.
Its intent is to catalog all human genes – the genome – supposedly listing every one of the 3 billion genetic "letters" that the body's cells contain. The letters correspond to chemicals strung together in the double-twisted DNA molecule. The "words" in DNA are spelled out in three-letter codes for amino acids, the building blocks of proteins – the stuff from which cells are made and the tools the cells use to conduct the chemistry that keeps life lively.
Such an encyclopedia promises to be a rich resource for the biologists and physicians of the future. Already its data have revealed intriguing insights into human genetic science.
But despite the impression that recent hype may have created, the book does not yet list all the genetic letters. Both groups still fall short of the 3 billion mark. Numerous errors remain to be corrected.
And many of the "surprises" supposedly revealed by the initial analyses merely confirm what most biologists already knew – or had begun to suspect.
For one thing, the new reports pegged the total number of human genes at less than 40,000 – perhaps even less than 30,000 – maybe only about twice as many genes as found in fruit flies.
While that count falls short of many previous estimates, it hardly presents biologists with any crisis of confidence in humanity's complexity.
Yet Craig Venter of Celera Genomics, the private company that turned the genome project from plodding science into a horse race, trumpeted the gene count as a philosophical epiphany.
"Everybody thought that there would be a gene in the genome for each of our traits or features," Dr. Venter said at the San Francisco meeting. "It's clearly not the case. ... This information goes a long way in helping to show that we are not hard-wired."
Actually, nobody (well, almost nobody) thought that every human feature corresponded to a single gene. Biologists have long known that genes can be cut and pasted; the body's complexity arises from subtle patterns of gene editing and gene activity. Different combinations of genes are active in different cells in different parts of the body. Genetic activity is often sensitive to signals from the outside world. Nobody needed a gene count to know that life is not irrevocably hard-wired.
A genetic cynic might even begin to wonder what was the greater accomplishment – cataloging the letters in the genetic code or orchestrating the circuslike publicity campaign that has mesmerized the world's media.
But that would be going a little too far. Even a less-than-complete Encyclopedia Genetica represents an information treasure not unlike the ancient library at Alexandria, the burning of which Sagan lamented in Cosmos.
Much of the history of human civilization was lost, Sagan noted, as the papyrus scrolls collected in Alexandria over centuries disintegrated in minutes. But now scientists have recovered another sort of human history, recorded as it happened, in the genomic data contained in DNA.
It's hard to say today what the consequences of this knowledge will someday be. So in the future, critics of today's genome hype may remark not that it was excessive, but that it was understated.
"We always, in a moment like this, tend to overestimate the immediate consequences," said Dr. Collins, "but underestimate the long-term consequences."
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