title: The GC-rich mitochondrial and plastid genomes of the green alga Coccomyxa give insight into the evolution of organelle DNA nucleotide landscape.
abstract: Most of the available mitochondrial and plastid genome sequences are biased towards adenine and thymine (AT) over guanine and cytosine (GC). Examples of GC-rich organelle DNAs are limited to a small but eclectic list of species, including certain green algae. Here, to gain insight in the evolution of organelle nucleotide landscape, we present the GC-rich mitochondrial and plastid DNAs from the trebouxiophyte green alga Coccomyxa sp. C-169. We compare these sequences with other GC-rich organelle DNAs and argue that the forces biasing them towards G and C are nonadaptive and linked to the metabolic and/or life history features of this species. The Coccomyxa organelle genomes are also used for phylogenetic analyses, which highlight the complexities in trying to resolve the interrelationships among the core chlorophyte green algae, but ultimately favour a sister relationship between the Ulvophyceae and Chlorophyceae, with the Trebouxiophyceae branching at the base of the chlorophyte crown.
authors: Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, Vancouver, British Columbia, Canada. smithdr@dal.ca
authors: David Roy
authors: DR
authors: Smith
authors: Fabien
authors: F
authors: Burki
authors: Takashi
authors: T
authors: Yamada
authors: Jane
authors: J
authors: Grimwood
authors: Igor V
authors: IV
authors: Grigoriev
authors: James L
authors: JL
authors: Van Etten
authors: Patrick J
authors: PJ
authors: Keeling
mesh_terms: D000595:Amino Acid Sequence; D001482:Base Composition / Q000235:genetics*; D001499:Bayes Theorem; D000460:Chlorophyta / Q000235:genetics*; D002874:Chromosome Mapping; D004247:DNA / Q000235:genetics*; D019143:Evolution, Molecular; D054629:Genome, Mitochondrial / Q000235:genetics*; D054627:Genome, Plastid / Q000235:genetics*; D016013:Likelihood Functions; D009711:Nucleotides / Q000235:genetics; D015388:Organelles / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D009711:Nucleotides; D004247:DNA