title: Complete sequence of the mitochondrial DNA of the red alga Porphyra purpurea. Cyanobacterial introns and shared ancestry of red and green algae.
abstract: The mitochondrial DNA (mtDNA) of Porphyra purpurea, a circular-mapping genome of 36,753 bp, has been completely sequenced. A total of 57 densely packed genes has been identified, including the basic set typically found in animals and fungi, as well as seven genes characteristic of protist and plant mtDNAs and specifying ribosomal proteins and subunits of succinate:ubiquinone oxidoreductase. The mitochondrial large subunit rRNA gene contains two group II introns that are extraordinarily similar to those found in the cyanobacterium Calothrix sp, suggesting a recent lateral intron transfer between a bacterial and a mitochondrial genome. Notable features of P. purpurea mtDNA include the presence of two 291-bp inverted repeats that likely mediate homologous recombination, resulting in genome rearrangement, and of numerous sequence polymorphisms in the coding and intergenic regions. Comparative analysis of red algal mitochondrial genomes from five different, evolutionarily distant orders reveals that rhodophyte mtDNAs are unusually uniform in size and gene order. Finally, phylogenetic analyses provide strong evidence that red algae share a common ancestry with green algae and plants.
authors.affiliation: Program in Evolutionary Biology, Canadian Institute for Advanced Research, 180 Dundas Street West, Toronto, Ontario M5G 1Z8, Canada. BurgerG@BCH.UMontreal.CA
authors.forename: G
authors.initials: G
authors.lastname: Burger
authors.forename: D
authors.initials: D
authors.lastname: Saint-Louis
authors.forename: M W
authors.initials: MW
authors.lastname: Gray
authors.forename: B F
authors.initials: BF
authors.lastname: Lang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D000460:Chlorophyta / Q000235:genetics*; D002874:Chromosome Mapping; D003062:Codon / Q000235:genetics; D000458:Cyanobacteria / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D007438:Introns; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D010944:Plants / Q000235:genetics; D011110:Polymorphism, Genetic; D011544:Pseudogenes; D012341:RNA, Ribosomal, 5S / Q000737:chemistry / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D016364:Reading Frames; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D000461:Rhodophyta / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
chemical_list: D003062:Codon; D004269:DNA, Bacterial; D004272:DNA, Mitochondrial; D012341:RNA, Ribosomal, 5S; D012343:RNA, Transfer; D004259:DNA-Directed DNA Polymerase