Why Sequence Six Archaea?

Archaea are the least well characterized of the three domains of life, and yet they share many important features with eukaryotes and are the key to understanding both the development of the eukaryotic cell and the origins and nature of the last universal common ancestor. In addition, many archaeal organisms are of interest in their own right because of their extremophilic properties (i.e., living at high temperature, low pH, or high salt concentration) and the uniqueness of their cellular organization.

JGI plans to sequence six archaeal genomes selected for their phylogenetic diversity and their ability to complement the genomes already published, thereby providing a fuller understanding of the major archaeal phyla. Three of the choices are methanogens, two from the order Methanomicrobiales, the only order of methanogens for which no representatives have yet been sequenced. The remaining methanogen, Methanothermus fervidus, is a hyperthermophilic representative of the Methanobacteriales and will be only the second genome characterized from this major taxon. JGI will also sequence a psychrophilic, phylogenetically distant halophile to complement the two published mesophilic halophile genomes. Two genomes from the kingdom Crenarchaeota will widen the extremely narrow phylogenetic scope of sequenced crenarchaeal genomes. The genome sequences will enable researchers to determine the set of genes common to all archaea and the gene sets defining the major subdivisions of the archaea, leading to a greater understanding of the biology and evolution of this domain.

This work will be of immense importance to evolutionary biologists and will further promote comparative genome analysis across the full biological spectrum. It will also help the community to refine and extend ongoing evolutionary debates addressing horizontal gene transfer. The genome sequences will greatly improve our understanding of the general nature of the amino acid changes in adaptation to high- or low-temperature environments. The genomes will also help the protein structure community to determine the structural features that allow proteins to operate at extremes of temperature, pH, and salinity. The genomes of the methanogens will give more insight into the metabolic and bioenergetic pathways required for the production of methane from waste material.

CSP project participants: Carl R. Woese (proposer), Gary Olsen, and Claudia Reich (Univ. of Illinois at Urbana-Champaign); Iain Anderson (JGI); Rick Cavicchioli (Univ. of New South Wales); Shil DasSarma (Univ. of Maryland Biotechnology Inst.); Harald Huber (Univ. Regensburg); Nikos Kyrpides (JGI), William Whitman (Univ. of Georgia).

Genome Portal Sites: Methanoculleus marisnigri JR1 , Thermofilum pendens Hrk 5