Partial sequences of mitochondrial 16S rRNA gene were obtained by PCR amplification for comparisons among nine species of glyptosternoid fishes and six species of non-glyptosternoids representing 10 sisorid genera. Th...Partial sequences of mitochondrial 16S rRNA gene were obtained by PCR amplification for comparisons among nine species of glyptosternoid fishes and six species of non-glyptosternoids representing 10 sisorid genera. There are compositional biases in the A-rich unpaired regions and G-rich paired regions. A-G transitions are primarily respon- sible for the Ts/Tv bias in unpaired regions. The overall sub- stitution rate in unpaired regions is almost two times higher than that in the paired regions. Saturation plots at compara- ble levels of sequence divergence demonstrate no saturation effects. Phylogenetic analyses using both maximum likeli- hood and Bayesian methods support the monophyly of Sis- oridae. Chinese sisorid catfishes are composed of two major lineages, one represented by (Gagata (Bagarius, Glyptotho- rax)) and the other by “glyptosternoids + Pseudecheneis”. The glyptosternoids may not be a monophyletic group. A previous hypothesis referring to Pseudecheneis as the sister group of monophyletic glyptosternoids, based on morpho- logical evidence, is not supported by the molecular data. Pseudecheneis is shown to be a sister taxon of Glaridoglanis. Pareuchiloglanis might be paraphyletic with Pseudexostoma and Euchiloglanis. Our results also support the hypothesis that Pareuchiloglanis anteanalis might be considered as the synonyms of Pareuchiloglanis sinensis, and genus Euchilo- glanis might have only one valid species, Euchiloglanis davidi.展开更多
文摘Partial sequences of mitochondrial 16S rRNA gene were obtained by PCR amplification for comparisons among nine species of glyptosternoid fishes and six species of non-glyptosternoids representing 10 sisorid genera. There are compositional biases in the A-rich unpaired regions and G-rich paired regions. A-G transitions are primarily respon- sible for the Ts/Tv bias in unpaired regions. The overall sub- stitution rate in unpaired regions is almost two times higher than that in the paired regions. Saturation plots at compara- ble levels of sequence divergence demonstrate no saturation effects. Phylogenetic analyses using both maximum likeli- hood and Bayesian methods support the monophyly of Sis- oridae. Chinese sisorid catfishes are composed of two major lineages, one represented by (Gagata (Bagarius, Glyptotho- rax)) and the other by “glyptosternoids + Pseudecheneis”. The glyptosternoids may not be a monophyletic group. A previous hypothesis referring to Pseudecheneis as the sister group of monophyletic glyptosternoids, based on morpho- logical evidence, is not supported by the molecular data. Pseudecheneis is shown to be a sister taxon of Glaridoglanis. Pareuchiloglanis might be paraphyletic with Pseudexostoma and Euchiloglanis. Our results also support the hypothesis that Pareuchiloglanis anteanalis might be considered as the synonyms of Pareuchiloglanis sinensis, and genus Euchilo- glanis might have only one valid species, Euchiloglanis davidi.
