Mother Nature's DNA

The Human Genome Project has not cured any diseases yet--but it's revolutionizing science in surprising ways


    AIR AND SEA: Besides searching the Galapagos for oceangoing genes, Venter is testing the air over New York City

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    It's not easy to culture wild microbes in the lab, but much can be learned by sequencing the genes contained in a sample of earth, air or water. Just this past April, scientists from the Joint Genome Institute (JGI), a Department of Energy lab in Walnut Creek, Calif., announced in the journal Science that they had for the first time identified the unique mixes of microbes that thrive in different sorts of ecosystems. In farm soil, for example, there are any number of genes that produce substances that break down plant material--rotting genes, you might call them. In seawater, by contrast, there are very few rotting genes but lots of genes that process salts. By understanding the microbial gene profile of a healthy environment, scientists will be able to gauge the health of other ecosystems.

    In the Sargasso Sea, meanwhile, Venter was shocked to find nearly 800 genes for making light-sensitive proteins like those found in the human retina--quadrupling the number of photoreceptors known to science. "This suggests," Venter wrote in New Scientist last May, "that some new type of light-driven biology may explain the Sargasso Sea's unexpectedly high diversity of species."

    But environmental indicators and surprising biology are only part of what makes wholesale gene prospecting so promising. Hydrogen has been touted as a clean-burning replacement for fossil fuels, for example, and, says Patrinos, "there are already bugs out there that produce hydrogen." If gene prospectors could isolate the responsible gene, he explains, and splice it into a common bacterium, just as genetic engineers have done for years with the gene that produces human insulin, "we can duplicate it on industrial scales."

    Or take ethanol, the gasoline substitute manufactured today mostly from corn. It currently takes a lot of harsh chemicals to process ethanol, but microbes could do the same thing. "I think it's doable within this decade," says Patrinos, "that we will develop a superbug that can make that conversion in a very clean way." Indeed, JGI, in collaboration with the San Diego-based biotech company Diversa, is sequencing communities of bacteria from the guts of termites in an effort to find genes that make hydrogen and ethanol. It's also looking for genes that enable microbes to metabolize radioactive waste.

    Hundreds more equally promising samples are being fed into the sequencers at JGI, at the J. Craig Venter Institute Joint Technology Center in Rockville, Md., and at other labs around the world. Venter's take from the Sargasso Sea was impressive enough on its own, but he is taking a new ocean sample every 200 miles or so as he circumnavigates the globe. Some 85% of the gene sequences he hauls up are unique to that site, suggesting that each 200-mile stretch of ocean represents a vastly different ecosystem. And that's just from scratching the surface, says JGI director Eddy Rubin: "There are whole domains of life that haven't been touched yet." --Reported by Melissa August/ Washington and Laura A. Locke/ Walnut Creek

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