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Title: Patterns of nucleotide change in mitochondrial ribosomal RNA genes and the phylogeny of piranhas
Authors: Orti, Guillermo
Petry, Paulo
Porto, Jorge Ivan Rebelo
Jegú, Michel
Meyer, Axel
Keywords: Dna, Mitochondrial
Mitochondrial Rna
Ribosome Rna
Rna 16s
Animals Tissue
Nucleotide Sequence
Protein Secondary Structure
Sequence Analysis
Base Composition
Base Sequence
Dna, Mitochondrial
Evolution, Molecular
Host-parasite Relations
Models, Genetic
Molecular Sequence Data
Nucleic Acid Conformation
Rna, Ribosomal
Rna, Ribosomal, 16s
Issue Date: 1996
metadata.dc.publisher.journal: Journal of Molecular Evolution
metadata.dc.relation.ispartof: Volume 42, Número 2, Pags. 169-182
Abstract: The patterns and rates of nucleotide substitution in mitochondrial ribosomal RNA genes are described and applied in a phylogenetic analysis of fishes of the subfamily Serrasalminae (Teleostei, Characiformes, Characidae). Fragments of 345 bp of the 12S and 535 bp of the 16S genes were sequenced for 37 taxa representing all but three genera in the subfamily. Secondary- structure models based on comparative sequence analysis were derived to characterize the pattern of change among paired and unpaired nucleotides, forming stem and loop regions, respectively. Base compositional biases were in the direction of A-rich loops and G-rich stems. Ninety-five percent of substitutions in stem regions were compensatory mutations, suggesting that selection for maintenance of base pairing is strong and that independence among characters cannot be assumed in phylogenetic analyses of stem characters. The relative rate of nucleotide substitution was similar in both fragments sequenced but higher in loop than in stem regions. In both genes, C-T transitions were the most common type of change, and overall transitions outnumbered transversions by a factor of two in 16S and four in 12S. Phylogenetic analysis of the mitochondrial DNA sequences suggests that a clade formed by the genera Piaractus, Colossoma, and Mylossoma is the sister group to all other serrasalmins and that the genera Myleus, Serrasalmus, and Pristobrycon are paraphyletic. A previous hypothesis concerning relationships for the serrasalmins, based on morphological evidence, is not supported by the molecular data. However, phylogenetic analysis of host-specific helminth parasites and cytogenetic data support the phylogeny of the Serrasalminae obtained in this study and provide evidence for coevolution between helminth parasites and their fish hosts.
metadata.dc.identifier.doi: 10.1007/BF02198843
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