Complete nucleotide sequence of the mitochondrial genome of Doliolum nationalis with implications for evolution of urochordates.
Complete nucleotide sequence of the mitochondrial genome of Doliolum nationalis with implications for evolution of urochordates.
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DOI：
10.1016/j.ympev.2004.10.002
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发表时间：
2005-02
影响因子：
4.1
通讯作者：
S. Yokobori;T. Oshima;H. Wada
中科院分区：
文献类型：
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作者：
S. Yokobori;T. Oshima;H. Wada
尾索动物多样性生活方式的演化历史可能影响脊椎动物的演化历史，因而引起了人们极大的兴趣。在这里，我们报告完整的线粒体（mt）的DNA序列的远洋海樽纲doliolid Dolioliusnationalis。doliolid mt基因组与其他海鞘（如Halocynthia和Ciona）共享trnM（uau）和trnG（ucu）的不寻常的tRNA。另一方面，doliolid mt基因组的基因顺序与迄今报道的任何海鞘物种或脊椎动物的基因顺序显著不同。12个蛋白质编码基因的氨基酸序列的系统发育分析强烈支持的姐妹分组的doliolids和Phlebobranchic海鞘Ciona，Stolidobranchic海鞘alocynthia作为外群，从而提供了强有力的支持海鞘类的paraphyly，已建议由18S rDNA的研究。考虑到海鞘类的同源性，海鞘类和海樽类的共同祖先很可能是固着的，就像现在的海鞘类一样，而海樽类随后进化出了远洋生活方式。
The evolutionary history of the diverse lifestyles adopted by urochordates has attracted intense interest because it may effect the evolutionary history of vertebrates. Here, we report the complete mitochondrial (mt) DNA sequence of the pelagic thaliacean doliolid Doliolum nationalis. The doliolid mt genome shares the unusual tRNAs of trnM(uau) and trnG(ucu) with other ascidians, such as Halocynthia and Ciona. On the other hand, the gene order of the doliolid mt genome is significantly different from that of any ascidian species or vertebrate reported to date. Phylogenetic analyses of the amino acid sequences of 12 protein-coding genes strongly support the sister-grouping of doliolids and the Phlebobranch ascidian Ciona, with the Stolidobranch ascidian alocynthia as the outgroup, thereby providing strong support for the paraphyly of ascidians, as has been suggested by 18S rDNA studies. Given the paraphyletic nature of ascidians, it seems likely that the common ancestor of ascidians and thaliaceans was sessile, as are the present-day ascidians, and that the thaliaceans subsequently evolved a pelagic lifestyle.