It may seem as if J. Craig Venter is on an extended vacation as he sails his 95-ft. luxury yacht on a 25,000-mile voyage around the world. But the iconoclastic scientist who took on a consortium of national governments in a race to map the human genome--and fought them to a photo finish five years ago--is actually hard at work. He's prospecting--not for gold but for DNA, applying the same techniques developed to decode human genes to the genes of microbes scooped from the ocean and out of the air. On a pilot voyage, through the Sargasso Sea in the North Atlantic, he found more than 1,800 new species of bacteria and viruses--a surprise, since he had always thought of the Sargasso as a biological desert, relatively devoid of life.
Indeed, half a decade after Venter and his archrival, Francis Collins, director of the National Human Genome Research Institute, stood together at the White House to announce that the human genome had been sequenced, biologists have come to re-evaluate just what that milestone really meant. Back then, it was widely assumed that the emerging science of human genomics would quickly lead to spectacular cures for cancer and other diseases and even allow couples to have "designer" babies with desirable traits plucked from a catalog.
Although researchers around the world have made solid progress in understanding the genetic basis of disease--and the pharmaceutical industry now relies on gene sequencing in its search for new drugs--revolutionary new treatments have yet to emerge. "It's actually extremely exciting," says Collins. "But we're still probably a decade or maybe 15 years away from the real revolution in medicine that genomics promises."
At the same time, however, scientists have come to appreciate what can be gained from decoding other genomes, from modern chimps and ancient cave bears to microscopic bacteria and viruses. As the cost of sequencing each base pair has dropped, from $10 in 1990 to less than 9¢ in 2002 to 1/10 of 1¢ today, researchers are doing more all the time. Although 99% of the planet's genomes have yet to be decoded, researchers have identified hundreds of thousands if not millions of genes, dwarfing the paltry 24,000 or so we carry in our DNA.
Additionally, scientists are getting a much better understanding of what individual genes do, no matter where they're from. The challenge, explains Venter, is to identify the genes that allow some microbes to change sunlight into sugars, others to absorb carbon dioxide from the air and still others to transform dead plant matter into clean-burning hydrogen.
So researchers have set out to look for those genes--and not just in the ocean. Venter is also sampling the air over New York City, and other scientists are looking into hot springs, digging into the ground and even testing toxic-waste sites. "You can pick up a gram of soil," says Aristides Patrinos, who oversees the Department of Energy's genome program, "and there's DNA in it. By sequencing that DNA, you can infer what's there in terms of diversity." As a rule, the more diverse a given ecosystem--the more genes present, even at the microbial level--the more resistant it is to damage.