The mitochondrial genome of Hydra oligactis (Cnidaria, Hydrozoa) sheds new light on animal mtDNA evolution and cnidarian phylogeny
The mitochondrial genome of Hydra oligactis (Cnidaria, Hydrozoa) sheds new light on animal mtDNA evolution and cnidarian phylogeny
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DOI：
10.1016/j.gene.2007.12.002
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发表时间：
2008-02-01
期刊：
影响因子：
3.5
通讯作者：
Lavrov, Dennis V.
中科院分区：
文献类型：
--
作者：
Kayal, Ehsan;Lavrov, Dennis V.
确定了水螅纲首个水螅属（刺胞目，水螅纲）的线粒体DNA （mtDNA）分子的16314个核苷酸序列。该序列包含13个能量通路蛋白、大小亚基rnas、蛋氨酸和色氨酸tRNAs的基因，这是刺胞动物的典型特征。所有基因都具有相同的转录取向，它们在基因组中的排列与水母相似。此外，coxI的部分拷贝以与其他基因相反的转录方向存在于分子的一端，形成线性mtDNA和线性线粒体质粒的部分反向末端重复特征。靠近分子至少一端的序列包含几个同核苷酸序列以及能够形成强二级结构的小反向重复序列，可能参与mtDNA的维持和表达。对H. oligactis和其他刺胞动物线粒体基因的系统发育分析支持Medusozoa假说，但也表明Anthozoa可能是副虫，其中octocorallians与Medusozoa的亲缘关系比与Hexacorallia的亲缘关系更近。后一种推论意味着刺虫是附生的，而珊瑚虫（而不是水母）是刺胞动物的祖先体类型。(C) 2007 Elsevier B.V.版权所有
The 16,314-nuceotide sequence of the linear mitochondrial DNA (mtDNA) molecule of Hydra oligactis (Cnidaria, Hydrozoa) - the first from the class Hydrozoa - has been determined. This sequence contains genes for 13 energy pathway proteins, small and large subunit rRNAs, and methionine and tryptophan tRNAs, as is typical for cnidarians. All genes have the same transcriptional orientation and their arrangement in the genome is similar to that of the jellyfish Aurelia aurita. In addition, a partial copy of coxI is present at one end of the molecule in a transcriptional orientation opposite to the rest of the genes, forming a part of inverted terminal repeat characteristic of linear mtDNA and linear mitochondrial plasmids. The sequence close to at least one end of the molecule contains several homonucleotide runs as well as small inverted repeats that are able to form strong secondary structures and may be involved in mtDNA maintenance and expression. Phylogenetic analysis of mitochondrial genes of H. oligactis and other cnidarians supports the Medusozoa hypothesis but also suggests that Anthozoa may be paraphyletic, with octocorallians more closely related to the Medusozoa than to the Hexacorallia. The latter inference implies that Anthozoa is paraphyletic and that the polyp (rather than a medusa) is the ancestral body type in Cnidaria. (C) 2007 Elsevier B.V. All rights reserved.