A conventional view delineates cellular life into only two basic types called prokaryotes and eukaryotes. The prokaryotes are further subdivided into the Bacteria and the
Archaea based on small subunit ribosomal RNA comparisons and conserved mechanisms for information processing. The study of
Archaeal prokaryotes has matured rapidly in part initiated by genomic science as well as a continuing interest in the biochemistry and metabolism of extremophiles.
The "concept" of
Archaea arose over 30 years ago when Woese and Fox (1977) proposed that prokaryotes were not a monophyletic group (single root) because of differences between their small subunit ribosomal RNA sequences. Instead, they defined two distinct evolutionary lineages represented by the Bacteria and the
Archaea (formerly called archaebacteria). This distinction has since received considerable support from diverse sources. A compelling example comes from whole genome sequencing studies that reveal extensive examples of genetic conservation common to the
Archaea but absent from the Bacteria and the Eukarya (eukaryotes).
Archaea are subdivided into four phyla of which two, the Crenarchaeota and the Euryarchaeota, are most intensively studied. The identity and function of the conserved features of the
Archaea remain enigmatic and are worthy of research endeavour.
- Archaea: New Models for Prokaryotic Biology
- Microbiology books
Labels: archaea, brief notes