Archaebacteria and the Three Kingdoms

L.A. Moran lamoran at gpu.utcc.utoronto.ca
Sun Apr 10 18:54:43 EST 1994


I have just had a chance to read Woese's most recent review (Woese 1994).
He recounts the history of biology from the classical period through the
dark ages (1950's and 1960's) and finally the renaissance in 1977 when
he published his first tree showing that archaebacteria were a separate
domain (Fox et al. 1977, Woese and Fox, 1977). Since 1977 Woese, according 
to Woese, has engaged in a constant struggle against idiots, such as myself, 
who remain skeptical.

In his own words,

     "Some 15 years ago, when the discovery of the Archaea was first
      reported, microbiologists and biologists in general reacted in 
      what can only be called an irrational way: the discovery was 
      generally rejected out of hand, even derisively dismissed. However,
      this is fully understandable; the discovery of a "third form of
      life" (as the Archaea was originally called) had breached a
      paradigm - and the good citizens were taking up arms to repel the
      invaders. The problem for me and my collaborators at that time
      (and since) became that of convincing biologists (especially
      microbiologists) that their outlook was flawed and needed to
      change. This is never easy, however; recalcitrance, bitterness,
      and a lot of vested interests are involved. The fact that I and
      my cohorts have been at this task for over a decade now, with
      only partial success, shows you how difficult changing a paradigm
      can be."

I find this language very offensive. It's not that I object to disagreements
and controversy - in fact I thrive on them - but I do object to the arrogance
of someone who is so convinced he is right that no other possibility seems
to exist. No where in this entire review is there any mention of the 
possibility that Woese could be wrong. Instead the tone is more appropriate
to someone writing his memoirs after winning a great battle. The average
reader will get the impression that the war is over, Three Domains has
triumphed, and now it's time to look back and ask how everyone could have
been so stupid. Well, not everyone .... there was at least one genius
who was able to guide us to the ultimate truth. The review makes it very
clear who the hero is.  (-:

Woese begins to sound more like a preacher than a scientist when he writes,

     "For me, the most pleasing aspect of the "new microbiology" is 
      the emerging connection between eukaryote and prokaryote. The
      discovery of the Archaea, i.e., finding that there exist two
      groups of prokaryotes no more related to one another than either
      is to the eukaryote, has been like adding a binocular component
      to previously monocular vision. With this finding the conceptual 
      wall that had divided the study of the prokaryote from that of the
      eukaryote began to crumble; and the rooting of the universial tree,
      which reveals the archaea to be specific relatives of the eukaryotes,
      will bring that wall down forever. Studying the archaea becomes
      doubly exciting when you know that in so doing you may find a
      key to the evolution and nature of the eukarytoic cell."

It must be nice to so certain about the earliest stages of evolution. 
Unfortunately many of the rest of us are not quite ready to jump on this
bandwagon or join the crusade. We are prepared to live with our walls
and our monocular vision for a little while longer. And we will still
find excitement in studying the Archaea even if they are not closely
related to eukaryotes. In fact studying the Archaea is doubly exciting
because it might show that the Three Domain hypothesis is wrong!

(Actually, I did join the crusade a few years ago and incorporated the idea
of three domains into my textbooks. Only in the past few years have I become
more skeptical as new data accumulates. Is there anyone else out there who
used to be a believer but is now back on the fence? Which way is the paradigm
shifting? Incidently, I abhor the current usage of the word "paradigm",
especially when one applies it to one's own work.)


Laurence A. Moran (Larry)
  
Woese, C.R. (1994) There must be a prokaryote somewhere: microbiology's
   search for itself. Microbiol. Rev. 58, 1-9.



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