Halobacterium volcanii

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Scientific classification

Also known as Haloferax volcanii

Description and Significance

Haloferax volcanii is an archaeon that can survive in environments of extreme salt concentrations. Halobacteria are located throughout the world in salt ponds and lakes, and may exist in the form of dormant or living cells, biopolymers in rocks, salt crystals, or as evaporates in desert regions.⁷ Haloferax volcanii in particular resides largely and predominantly in the bottom sediment of the Dead Sea, and are distinct from other organisms in their class in a few ways.²

H. volcanii are presumed to have been among the first living organisms on Earth when environmental conditions were much harsher than they are now. Though this is still highly debated, such a notion would correlate with the suggestion that H. volcanii may be present on and able to withstand the harsh conditions of Mars.⁷ Along with their ability to withstand harsh conditions is H. volcanii’s extensive ability for DNA repair. H. volcanii are also the first kind of archaeon to show horizontal gene transfer involving phage-mediated transduction, assimilation of naked DNA and conjugation, demonstrating importance and implications of surface proteins.⁶

Genome structure

Only one strain of Haloferax volcanii (Haloferax volcanii DS2) has a mapped genome. DS2 contains 4.01 million base pairs with approximately 4209 predicted genes. The most recent genome sequence draft was performed in April of 2007 by the Institute for Genomic Research. DS2 is found to have one chromosome and four plasmids. The chromosome has 2847757 base pairs and is 66.64% GC. Plasmid pHV4 has 635786 base pairs and is 61.67% GC. pHV 3 is 437906 base pairs and is 65.56% GC. pHV2 is 6359 base pairs and is 56.06% GC. Lastly, plasmid pHV1 is 85092 base pairs and is 55.5% GC.⁴