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用PCR方法获得了南方鲇(Silurus meridionalis)的线粒体基因组全序列,长度为16533bp,南方鲇线粒体基因组中A和T的含量略高((A+T)为55.17%),12S rRNA,16S rRNA,tRNA和控制区的(A+T)含量分别为52.44%,55.23%,55.97%和60.24%).基于选取的36种代表性种类线粒体全序列中的11个蛋白编码基因,构建了骨鳔鱼类系统发育树,并以骨鳔鱼类化石记录为标定点,运用松散分子钟方法估算物种分化时间.结果表明,耳鳔系鱼类为强烈支持的单系,鲤形目位于该类群的基部,脂鲤目和电鳗目构成姐妹群,然后和鲇形目构成姐妹群.骨鳔鱼类起源于三叠纪(约为231Mya),耳鳔系起源于三叠纪晚期(约为216Mya),其代表类群均起源于侏罗纪晚期(鲇形目、鲤形目、脂鲤目、电鳗目的分化发生在161～139Mya),南方鲇的物种分化时间约为白垩纪中期,估算的分化时间远早于化石记录.
The full-length mitochondrial DNA sequence of Silurus meridionalis was obtained by polymerase chain reaction (PCR). The total length of mitochondrial genome was 16533bp. The content of A and T in mitochondrial genome was slightly higher (A + T 55.17%), 12S rRNA, 16S rRNA, (A + T) content of tRNA and control region were 52.44%, 55.23%, 55.97% and 60.24%, respectively.) Based on the eleven protein coding genes in the 36 representative mitochondrial DNA sequences, Phylogenetic tree was constructed and the fossil records of the fishes were used as the calibration points.The species differentiation time was estimated by the method of loose molecular clock.The results showed that the sole line , Fat carp and electric eel head to form a sister group, and then form a sister group and Castanopsis. Skeletal fish originated in the Triassic (about 231Mya), ears originated in the Late Triassic (about 216Mya) , And its representative groups originated in the late Jurassic (the order Phasianidae, Cyprinidae, Epinephelus cephalothorax and Anguilla angioma occurred in 161 ~ 139Mya), while the species divergence time in Ephemeroptera was about the mid-Cretaceous. The estimated differentiation The time is far earlier than the fossil record.