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克隆并测定了暗纹东方鲀线粒体基因组(m tDNA)含完整的细胞色素氧化酶亚基Ⅲ(CO III)及其下游70 bp的tRNAG ly序列。CO III基因编码框包含786个核苷酸,编码262个氨基酸的蛋白质。鱼类CO III的序列组成对A+T核苷酸的偏倚程度比较低。通过暗纹东方鲀与GenBank中8个目12种鱼类的CO III序列同源性比较,显示暗纹东方鲀与这些鱼类的CO III基因具有较高的同源性。根据暗纹东方鲀与鲀目其他5种鱼的CO III基因序列所建立的进化树,与传统的分类地位相吻合。推定的tR-NA的二级结构具有典型的三叶草型结构。根据CO III序列构建的分子进化树分析,认为在采用线粒体基因序列进行分子进化分析时,应综合考虑物种遗传变异的特点。
The mitochondrial genome (m tDNA) of the Takifugu obscurus was cloned and sequenced. The complete cytochrome oxidase subunit III (CO III) and its downstream 70 bp tRNAG ly were sequenced. The CO III gene coding frame contains a 786-nucleotide protein that encodes 262 amino acids. The sequence composition of fish CO III is less biased toward A + T nucleotides. Comparison of the CO III sequence homologies among 8 species of 12 species of fish in GenBank revealed that there was a high homology between these genes and the CO III gene of these species. The phylogenetic tree based on the CO III gene sequences of the other five species of Takifugu obscurus and Hymenoptera matches the traditional taxonomic status. The secondary structure of the putative tR-NA has a typical cloverleaf structure. According to the molecular phylogenetic tree based on the CO III sequence, it is considered that the genetic variation of the species should be considered when using the mitochondrial DNA sequence analysis.