title: The complete chloroplast and mitochondrial DNA sequence of Ostreococcus tauri: organelle genomes of the smallest eukaryote are examples of compaction.
abstract: The complete nucleotide sequence of the mt (mitochondrial) and cp (chloroplast) genomes of the unicellular green alga Ostreococcus tauri has been determined. The mt genome assembles as a circle of 44,237 bp and contains 65 genes. With an overall average length of only 42 bp for the intergenic regions, this is the most gene-dense mt genome of all Chlorophyta. Furthermore, it is characterized by a unique segmental duplication, encompassing 22 genes and covering 44% of the genome. Such a duplication has not been observed before in green algae, although it is also present in the mt genomes of higher plants. The quadripartite cp genome forms a circle of 71,666 bp, containing 86 genes divided over a larger and a smaller single-copy region, separated by 2 inverted repeat sequences. Based on genome size and number of genes, the Ostreococcus cp genome is the smallest known among the green algae. Phylogenetic analyses based on a concatenated alignment of cp, mt, and nuclear genes confirm the position of O. tauri within the Prasinophyceae, an early branch of the Chlorophyta.
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Ghent University, Ghent, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: Robbens
authors.forename: Evelyne
authors.initials: E
authors.lastname: Derelle
authors.forename: Conchita
authors.initials: C
authors.lastname: Ferraz
authors.forename: Jan
authors.initials: J
authors.lastname: Wuyts
authors.forename: Hervé
authors.initials: H
authors.lastname: Moreau
authors.forename: Yves
authors.initials: Y
authors.lastname: Van de Peer
mesh_terms: D000460:Chlorophyta / Q000235:genetics*; D048028:DNA, Algal / Q000737:chemistry / Q000235:genetics; D018742:DNA, Chloroplast / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D030541:Databases, Genetic; D005057:Eukaryotic Cells / Q000378:metabolism*; D023061:Gene Order; D008957:Models, Genetic; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D048028:DNA, Algal; D018742:DNA, Chloroplast; D004272:DNA, Mitochondrial