Abstract
The SAR11 clade consists of very small, heterotrophic marine alpha-proteobacteria that are found throughout the oceans, where they account for about 25% of all microbial cells. Pelagibacter ubique, the first cultured member of this clade, has the smallest genome and encodes the smallest number of predicted open reading frames known for a free-living microorganism. In contrast to parasitic bacteria and archaea with small genomes, P. ubique has complete biosynthetic pathways for all 20 amino acids and all but a few cofactors. P. ubique has no pseudogenes, introns, transposons, extrachromosomal elements, or inteins; few paralogs; and the shortest intergenic spacers yet observed for any cell.
Publication types
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
- Alphaproteobacteria / classification
- Alphaproteobacteria / genetics*
- Alphaproteobacteria / isolation & purification
- Alphaproteobacteria / physiology
- Bacterial Proteins / genetics
- Bacterial Proteins / metabolism
- Base Composition
- Biological Evolution
- Carbon / metabolism
- Computational Biology
- DNA, Bacterial / chemistry
- DNA, Bacterial / genetics
- DNA, Intergenic
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Genome, Bacterial*
- Membrane Transport Proteins / genetics
- Membrane Transport Proteins / metabolism
- Molecular Sequence Data
- Oceans and Seas
- Phosphates / metabolism
- Phylogeny
- Seawater / microbiology*
- Selection, Genetic
- Sigma Factor / genetics
- Thymidylate Synthase / genetics
Substances
- Bacterial Proteins
- DNA, Bacterial
- DNA, Intergenic
- Membrane Transport Proteins
- Phosphates
- Sigma Factor
- Carbon
- Thymidylate Synthase