(030728 created)
- Woese CR, Fox GE.
- Phylogenetic structure of the prokaryotic domain: the primary kingdoms.
- Proc Natl Acad Sci U S A. 1977 Nov;74(11):5088-90.
Summary
A phylogenetic analysis based upon ribosomal RNA sequence characterization reveals that living systems represent one of three aboriginal lines of descent: (i) the eubacteria, comprising all typical bacteria; (ii) the archaebacteria, containing methanogenic bacteria; and (iii) the urkaryotes, now represented in the cytoplasmic component of eukaryotic cells.
Hori's Comments: By using the data in this table, Dr. Woese constructed phylogenetic trees shown below, but not in the original paper. These trees were reported first in popular science magazines such as Scientific American or Carolina Biological Supply Company, but never shown in journals with critical referee systems at least I know. Length of the branches in the tree that must be deduced from the SAB of the table are showing no correlation to it, suggesting no scientific backgrounds for branch length.
- Woese CR.
- Archaebacteria.
- Sci. Amer. 244 (6) : 94-106 (1981).
Summary
These unusual bacteria are genealogically neither prokaryotes nor eukaryotes. This discovery means there are not two lines of descent but three: the archaebacteria, the true bacteria and the eukaryotes.
THREE PRIMARY KINGDOMS are proposed by the author to comport with the discovery that the archaebacteria are fundamentally different from all other bacteria, which are designated the eubacteria, or true bacteria. Both eubacteria and archaebacteria are alike in being prokaryotic cells: simple cells that lack a nucleus and are very different in their structural properties from eukaryotic cells, which have a nucleus and several other subcellular organelles. Genealogically, however, archaebacteria and eubacteria are no more closely related to each other than either group is to eukaryotes. It is proposed that the archaebacteria , the eubacteria and an urkaryote - the original eukaryotic cell - stemmed from a common ancestor (the progenote) much simpler than the simplest present-day cells (prokaryotes). Eukaryotes evolved after the urkaryote became a "host" for bacterial endosymbionts that developed into mitochondrion and chloroplast.
(Figure legend of the article)
- THE ORIGIN OF LIFE
- Carl R. Woese
- Carolina Biology Readers No. 13 (1984)
- Burlington, North Carolina 27215.
Figure 21. The universal phylogenetic tree. All known living froms fall into one of the tree basic categories: the archaebacteria, the eubacteria, and the eukaryotes. The first two are prokaryotic cells; that is, they are small, do not have nuclear membranes or organelles, etc. However, the archaebacteria and eubacteria are not specifically related to one another. From fossil evidence bacteria appear to have been in existence for at least 3.5 billion years and perhaps longer, far before the advent of the eukaryotic groups. Each of the three major groups of organisms is quite distinct on the molecular level, differing from the others in the molecular details of their common cellular processes. (Figure legend of the article)