title: Rapid evolution of the intergenic T-P spacer in the mtDNA of Arctic cod Arctogadus glacialis.
abstract: A noncoding intergenic spacer has previously been reported in mtDNA of Gadiformes. Here we present sequence information from two other cod species and variation within three species to clarify the evolution of this region. A general feature of the T-P spacer is high variation and folding into two or three hairpins. The variation among species both in structure of the region and sequence variation reflects the phylogenetic relationship of the species. A unique pattern is found within Arctic cod, Arctogadus glacialis, in which tandem repeat motifs result in new stable secondary structures. There is large variation in size of the region both within (heteroplasmy) and among individuals. A duplicated insertion is found in Greenland cod, Gadus ogac, at the same position as a corresponding duplication in Atlantic cod, Gadus morhua.
authors.affiliation: Department of Biology, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland. snaebj@hi.is
authors.forename: Snaebjörn
authors.initials: S
authors.lastname: Pálsson
authors.forename: Jonas
authors.initials: J
authors.lastname: Paulsen
authors.forename: Einar
authors.initials: E
authors.lastname: Arnason
mesh_terms: D000818:Animals; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D048388:Gadiformes / Q000235:genetics*; D014644:Genetic Variation; D009690:Nucleic Acid Conformation; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D004272:DNA, Mitochondrial; D021903:DNA, Ribosomal Spacer; D012343:RNA, Transfer