Phylogenetic structure of the prokaryotic domain: the primary kingdoms

Proc Natl Acad Sci U S A. 1977 Nov;74(11):5088-90. doi: 10.1073/pnas.74.11.5088.


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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacteria / classification
  • Cells*
  • Eukaryotic Cells
  • Phenotype
  • Phylogeny*
  • Prokaryotic Cells*