"Thermotoga was selected because it is near the base of the Woesean tree," says Craig Venter, TIGR chief scientific officer and president of nearby Celera Genomics Corp. The Woesean tree is the three-pronged depiction of the domains of life named for Carl Woese, the University of Illinois microbiologist who discovered the Archaea in 1977.2 The Archaea are microorganisms that lack nuclei as do traditional Eubacteria, yet have transcriptional and translational machinery and other characteristics more like the nucleated Eukarya. Thermotoga and another thermophilic bacterium, Aquifex aeolicus, have been jockeying for a coveted position near the part of the tree base where the Archaea and Eubacteria diverge from a shared ancestor. DNA sequence comparisons give conflicting information as to which microbe has more ancient roots, depending on which genes are scrutinized. For example, the Woesean tree and much of modern systematics are based on ribosomal...
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