Magazine article The Wilson Quarterly

The Empire Underground

Magazine article The Wilson Quarterly

The Empire Underground

Article excerpt

Twenty-five years ago, Illinois scientist Carl Woese identified an entirely new form of life. His discovery upended the traditional notion that all living things on Earth fall into five kingdoms and challenged our understanding of evolution and the origin of life. All he had to do was persuade his fellow scientists.

Late one evening about a quarter-century ago, in a dimly lit laboratory in Urbana, Illinois, a middle-aged scientist sat crouched over a lightbox that illuminated a large sheet of translucent photographic film. Imprinted on the film were rows of dark bands representing the nucleotide sequence of genetic material that had been isolated from several microbes. The bluish glow from the lightbox filled the room, casting giant shadows on the walls and revealing the man's face. His brow was wrinkled as he focused intently on various details of the film. He lifted his head momentarily and shook it as if in disbelief, rubbed his eyes, then looked again.

The bar code-like pattern exposed on the photographic film was the culmination of many days of tedious preparatory work. Each row represented RNA (ribonucleic acid) fragments from a different organism, and by quantifying the similarity in the location and width of the bands in each row, the scientist could gauge the genetic similarity among the organisms. This was in fact the repetition of an analysis he had performed some days earlier. He couldn't believe the results the first time, but here they were again. He had checked and double-checked all aspects of the procedure. This was not some aberration caused by a mix-up in the chemicals he had used or the accidental switching of samples. The results, if they could be confirmed by additional tests, could mean only one thing--he had made one of the most important scientific discoveries of the 20th century: he had identified not merely a new species, but an entire new kingdom, or super-kingdom, of organisms.

The scientist was Dr. Carl Woese (pronounced "woes") of the University of Illinois, and the year was 1976. In reality, the discovery unfolded over many days, nights, and weeks. The microbe that revealed its secret and eventually sparked a revolution in biology was considered at the time to be nothing more than an obscure type of bacterium known as a methanogen. The organism draws its name from the methane, or "natural gas," it produces as a byproduct of its metabolism. Indeed, it is now believed that much of the methane gas beneath the Earth's surface has been produced by methanogens. These soil organisms also produce the combustible "marsh gas" that sometimes hovers over swamps and rice paddies.

What Carl Woese conclusively established in 1976 was that, although the methanogens look like common bacteria under a microscope, genetically they are as distinct from bacteria as bacteria are from plants or animals. In fact, on a genetic basis, the methanogens have less in common with bacteria than a redwood tree or fungus has with you or me. If plants, animals, and bacteria were to be considered separate kingdoms, Woese reasoned, then so must the methanogens.

As Woese expanded his analyses, he soon found that the methanogens were not the only "bacteria" that should fall into the unique genetic category he had discovered. He began referring to the new category as a "domain" and gave it the name "Archae-bacteria," or "ancient bacteria." Later this would be changed simply to "Archaea" to more sharply distinguish the domain from bacteria and other forms of life. Woese recognized that these findings would shake our concept of the evolutionary "tree of life" down to its roots. What he could not foresee were the personal and professional battles he would have to fight within the world of science to gain acceptance and understanding of his revolutionary discovery.

I first met Woese in the fall of 1998. I arrived in Urbana on a Sunday afternoon, although our meeting wasn't scheduled until the following morning. …

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