November 1, 1977 (a Tuesday)

Carl Woese

On this date, the American microbiologist and physicist Carl Woese published a report in the Proceedings of the National Academy of Sciences (PNAS) in which he defined the Archaeabacteria (a new super-kingdom of life) by phylogenetic analysis of 16S ribosomal RNA.  This technique was pioneered by Woese and is now standard practice. By 1990 Woese shortened the name Archaebacteria to Archaea and adopted the term “domains” for the three new branches of life: Bacteria, Archaea, and Eukarya. Archaea are neither Bacteria nor Eukaryotes. In other words, they are Prokaryotes that are not Bacteria. More than twenty kingdoms exist under the domains in the tree of life, far more than the five original kingdoms suggested by R.H. Whittaker in 1969. In fact, Woese found that Archaea are more closely related to Eukarya (plants, animals, fungi, etc.) than to Bacteria. This accounted for the renaming of Archaebacteria, the original name given by Woese, to Archaea.

According to Woese:

The archaea are unique organisms. While prokaryotes in the cytological sense, they are actually more closely related to eukaryotes than to the bacteria. They are of particular interest for this reason alone-they are simple organisms whose study should provide insights into the nature and evolution of the eukaryotic cell. Their study is also central to an understanding of the nature of the ancestor common to all life. The archaea are, of course, interesting in their own right. The group contains both the methanogens and numerous organisms that grow at extremely high temperatures (in some cases above 100°C). As such, they provide potential insights into mechanisms of thermophilia and methanogenesis.

by Carl Woese

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 concepts of evolutionary radiation, but Woese appears to have been vindicated in his convictions.

References:

Advertisements

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s