Wang Ying, Guo Rui, Li Hua, Zhang Xiuyue, Du Jun, Song Zhaobin
Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu 610064, PR China.
Mar Genomics. 2011 Sep;4(3):221-8. doi: 10.1016/j.margen.2011.06.003. Epub 2011 Jul 7.
The complete mitochondrial DNA genome of the Sichuan taimen (Hucho bleekeri) was determined by the long and accurate polymerase chain reaction (LA-PCR) and primer walking sequence method. The entire mitochondrial genome of this species is 16,997bp in length, making it the longest among the completely sequenced Salmonidae mitochondrial genomes. It consists of two ribosomal RNA (rRNA) genes, 13 protein-coding genes, 22 transfer RNA (tRNA) genes, and one control region (CR). The gene arrangement, nucleotide composition, and codon usage pattern of the mitochondrial genome are similar to those of other teleosts. A T-type mononucleotide microsatellite and an 82bp tandem repeat were identified in the control region, which were almost identical among the three H. bleekeri individuals examined. Both phylogenetic analyses based on 12 concatenated protein-coding genes of the heavy strand and on just the control region show that H. bleekeri is a basal species in Salmoninae. In addition, Salmo, Salvelinus and Oncorhynchus all represent monophyletic groups, respectively. All freshwater species occupied basal phylogenetic positions, and also possessed various tandem repeats in their mitochondrial control regions. These results support established phylogenetic relationships among genera in Salmonidae based on morphological and molecular analyses, and are consistent with the hypothesis that Salmonidae evolved from freshwater species.
通过长片段精确聚合酶链反应（LA-PCR）和引物步移测序法测定了四川哲罗鲑（Hucho bleekeri）的完整线粒体DNA基因组。该物种的线粒体基因组全长16,997bp，是已完全测序的鲑科线粒体基因组中最长的。它由两个核糖体RNA（rRNA）基因、13个蛋白质编码基因、22个转运RNA（tRNA）基因和一个控制区（CR）组成。线粒体基因组的基因排列、核苷酸组成和密码子使用模式与其他硬骨鱼相似。在控制区鉴定出一个T型单核苷酸微卫星和一个82bp的串联重复序列，在所检测的3个四川哲罗鲑个体中几乎完全相同。基于重链12个串联蛋白质编码基因和仅基于控制区的系统发育分析均表明，四川哲罗鲑是鲑亚科的一个基部物种。此外，鲑属（Salmo）、红点鲑属（Salvelinus）和大麻哈鱼属（Oncorhynchus）均分别代表单系类群。所有淡水物种都占据基部系统发育位置，并且在其线粒体控制区也拥有各种串联重复序列。这些结果支持了基于形态学和分子分析所确立的鲑科各属之间的系统发育关系，并且与鲑科起源于淡水物种的假说一致。
