title: The genome of Nanoarchaeum equitans: insights into early archaeal evolution and derived parasitism.
abstract: The hyperthermophile Nanoarchaeum equitans is an obligate symbiont growing in coculture with the crenarchaeon Ignicoccus. Ribosomal protein and rRNA-based phylogenies place its branching point early in the archaeal lineage, representing the new archaeal kingdom Nanoarchaeota. The N. equitans genome (490,885 base pairs) encodes the machinery for information processing and repair, but lacks genes for lipid, cofactor, amino acid, or nucleotide biosyntheses. It is the smallest microbial genome sequenced to date, and also one of the most compact, with 95% of the DNA predicted to encode proteins or stable RNAs. Its limited biosynthetic and catabolic capacity indicates that N. equitans' symbiotic relationship to Ignicoccus is parasitic, making it the only known archaeal parasite. Unlike the small genomes of bacterial parasites that are undergoing reductive evolution, N. equitans has few pseudogenes or extensive regions of noncoding DNA. This organism represents a basal archaeal lineage and has a highly reduced genome.
authors.affiliation: Diversa Corporation, 4955 Directors Place, San Diego, CA 92121, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Waters
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hohn
authors.forename: Ivan
authors.initials: I
authors.lastname: Ahel
authors.forename: David E
authors.initials: DE
authors.lastname: Graham
authors.forename: Mark D
authors.initials: MD
authors.lastname: Adams
authors.forename: Mary
authors.initials: M
authors.lastname: Barnstead
authors.forename: Karen Y
authors.initials: KY
authors.lastname: Beeson
authors.forename: Lisa
authors.initials: L
authors.lastname: Bibbs
authors.forename: Randall
authors.initials: R
authors.lastname: Bolanos
authors.forename: Martin
authors.initials: M
authors.lastname: Keller
authors.forename: Keith
authors.initials: K
authors.lastname: Kretz
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Lin
authors.forename: Eric
authors.initials: E
authors.lastname: Mathur
authors.forename: Jingwei
authors.initials: J
authors.lastname: Ni
authors.forename: Mircea
authors.initials: M
authors.lastname: Podar
authors.forename: Toby
authors.initials: T
authors.lastname: Richardson
authors.forename: Granger G
authors.initials: GG
authors.lastname: Sutton
authors.forename: Melvin
authors.initials: M
authors.lastname: Simon
authors.forename: Dieter
authors.initials: D
authors.lastname: Soll
authors.forename: Karl O
authors.initials: KO
authors.lastname: Stetter
authors.forename: Jay M
authors.initials: JM
authors.lastname: Short
authors.forename: Michiel
authors.initials: M
authors.lastname: Noordewier
mesh_terms: D017360:Arabidopsis / Q000382:microbiology; D001105:Archaea / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D005075:Biological Evolution; D019641:DNA, Archaeal / Q000235:genetics; D015723:Gene Library; D020745:Genome, Archaeal; D010802:Phylogeny
chemical_list: D019641:DNA, Archaeal