Symposium marks 30th anniversary of discovery of third doma...(eir ribosomal RNA that are distinctive. ...)

This surprising discovery came when the researchers looked at the ribosomal RNA (rRNA) of a group of methane-generating microbes that had been classified as bacteria. Illinois microbiology professor Ralph Wolfe, an expert on these methanogens, was a member of Woeses team, along with postdoctoral researcher George Fox, graduate student William Balch and lab technician Linda Magrum.

Of all the numerous suggestions we had gotten for organisms to study, the one I solicited from my colleague, Ralph Wolfe, turned out to be the most important, Woese wrote in an account of the discovery. Ralph was in the process of working out the biochemistry of methanogenesis, which made it natural for him to suggest we characterize the methanogens.

Wolfe was one of only a handful of researchers studying methanogens in the mid-1970s. These organisms were notoriously difficult to grow in culture because they could survive only in an oxygen-free atmosphere that was rich in hydrogen and carbon dioxide. Balch, a graduate student in Wolfes lab, had found a way to create a sealed and pressurized atmosphere inside a test tube that would support these organisms, however. Using this technique, a methanogen now called M. bryantii, was grown in sufficient quantities for study.

Woese had already found a collection of rRNA sequences that were specific to bacteria, and another set of sequences unique to plants, animals and other eukarya. When he sequenced the ribosomal RNA of Wolfes methanogen, however, he found that it was strikingly different from that of eukarya and bacteria. Although it shared some universal sequences with the other organisms, it also carried its own unique set of sequences that did not fit with either group. It was neither fis
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