Carl Woese

Carl Richard Woese (born July 15 1928, Syracuse, New York) is an American microbiologist famous for defining the Archaea (a new domain or kingdom of life) in 1977 by phylogenetic taxonomy of 16S ribosomal RNA, a technique pioneered by Woese and which is now standard practice. He was also the originator of the RNA world hypothesis in 1967, although not by that name. He currently holds the Stanley O. Ikenberry Chair and is Professor of Microbiology at the University of Illinois at Urbana-Champaign.

Having defined Archaea as a new domain, Woese redrew the taxonomic tree. His three-domain system, based upon genetic relationships rather than obvious morphological similarities, divided life into 23 main divisions, all incorporated within three domains: Bacteria, Archaea, and Eucarya. Archaea are neither Bacteria nor Eukaryotes. Looked at another way, they are Prokaryotes which are not Bacteria.

The tree of life elucidated by Woese is noteworthy for its demonstration of the overwhelming diversity of microbial lineages; single-celled organisms represent the vast majority of the biosphere's genetic, metabolic, and ecosystem niche diversity. This is surprising to some, given our familiarity with the macrobiological world. As microbes are responsible for many biogeochemical cycles and are crucial to the continued function of the biosphere, Woese's efforts to clarify the evolution and diversity of microbes provided an invaluable service to ecologists and conservationists.



The acceptance of the validity of Woese's classification was a slow and painful process. Famous figures, including Salvador Luria and Ernst Mayr, objected to his division of the prokaryotes. Not all criticism of him was restricted to the scientific level. Not without reason has Woese been dubbed "Microbiology's Scarred Revolutionary" by the journal Science. The growing amount of supporting data led the scientific community in general to accept the Archaea by the mid-1980s. A shrinking minority of scientists still adhere to outmoded conceptions of evolutionary radiation, but Woese appears to have been vindicated in his convictions.

Woese also conjectured an era in which there was a considerable amount of lateral transfer of genes between organisms. Species formed when organisms stopped treating genes from other organisms with equal importance to their own genes. Lateral transfer during this period was responsible for the fast early evolution of complex biological structures.

Woese's work is also significant in terms of its implications for the search for life on other planets. Prior to Woese, Archaea were thought to be extreme organisms that had evolved from the organisms that are more familiar to us. Many scientists now believe they are ancient, and may have robust evolutionary connections to the first organisms to live on Earth. Organisms similar to those Archaea that exist in extreme environments may have found a foothold on other planets, some of which are known to harbor conditions conducive to extremophile life.

Woese was a MacArthur Fellow in 1984, was made a member of the National Academy of Sciences in 1988, received the Leeuwenhoek Medal (microbiology's highest honor) in 1992, and was a National Medal of Science recipient in 2000. In 2003, he received the Crafoord Prize from the Royal Swedish Academy of Sciences. In 2006, he was made a foreign member of the Royal Society.