The complete sequences and gene organisation of the mitochondrial genomes of the heterodont bivalves Acanthocardia tuberculata and Hiatella arctica--and the first record for a putative Atpase subunit 8 gene in marine bivalves.
The complete sequences and gene organisation of the mitochondrial genomes of the heterodont bivalves Acanthocardia tuberculata and Hiatella arctica--and the first record for a putative Atpase subunit 8 gene in marine bivalves.
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DOI：
10.1186/1742-9994-3-13
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发表时间：
2006-09-01
影响因子：
2.8
通讯作者：
Steiner G
中科院分区：
文献类型：
--
作者：
Dreyer H;Steiner G
线粒体（mt）基因排列在软体动物尤其是双壳贝类中具有高度的变异性。在迄今为止发表的30个完整的软体动物线粒体基因组中，只有一个是异齿双壳类，尽管这是物种数量最多样化的分类单元。我们确定了完整的序列Acanthocardia tuberculata和Hiatella arctica的线粒体基因组，（软体动物，双壳类，Heterodonta），并描述其基因内容和基因组组织，以评估这些功能之间的双壳类和它们的价值的系统发育推断的变异。结果表明，刺心藻线粒体基因组的大小为16.104bp，北极海牛线粒体基因组的大小为18.244bp。Acanthocardia mt-genome包含12个典型的蛋白质编码基因，缺乏Atpase亚基8（atp 8）基因，因为所有已发表的海洋双壳类。与此相反，完整的atp 8基因存在于Hiatella arctica中。另外，在对菲律宾蛤仔线粒体基因组进行重新注释时，我们发现了一个可能截短的atp 8基因。这里报告的两个mt基因组编码同一条链上的所有基因，并具有额外的trnM。在Acanthocardia中存在几个大的非编码区。其中一个包含3.5个几乎相同的167 bp动机拷贝。在Hiatella中，NADH脱氢酶亚基（nad）6基因的3'末端与相邻的非编码区一起重复。Hiatella的基因排列与已知的所有其他软体动物线粒体基因组都有明显的不同，Acanthocardia的基因排列与Venerupis philippinarum的基因排列很少相同。氨基酸和核苷酸水平的系统发育分析有力地支持了异齿亚目以及尖心属和金星属的姐妹群关系。单系双壳类只能通过核苷酸数据集的贝叶斯推断来解决。在所有其他的分析中，这两个蚌类物种，因为只有那些基因位于两条链上的物种，不与其余的双壳类组合在一起。这里报告的两个mt基因组增加和强调了双壳类和软体动物类群中基因顺序的高度变异性和重复的存在。一些基因组特征，如atp 8基因的缺失或所有基因编码在同一条链上，在双壳类中是同源的。这些特征、基因顺序和核苷酸序列数据显示了在较低分类水平上解决系统发育模式的巨大潜力。
Mitochondrial (mt) gene arrangement is highly variable among molluscs and especially among bivalves. Of the 30 complete molluscan mt-genomes published to date, only one is of a heterodont bivalve, although this is the most diverse taxon in terms of species numbers. We determined the complete sequence of the mitochondrial genomes of Acanthocardia tuberculata and Hiatella arctica, (Mollusca, Bivalvia, Heterodonta) and describe their gene contents and genome organisations to assess the variability of these features among the Bivalvia and their value for phylogenetic inference. The size of the mt-genome in Acanthocardia tuberculata is 16.104 basepairs (bp), and in Hiatella arctica 18.244 bp. The Acanthocardia mt-genome contains 12 of the typical protein coding genes, lacking the Atpase subunit 8 (atp8) gene, as all published marine bivalves. In contrast, a complete atp8 gene is present in Hiatella arctica. In addition, we found a putative truncated atp8 gene when re-annotating the mt-genome of Venerupis philippinarum. Both mt-genomes reported here encode all genes on the same strand and have an additional trnM. In Acanthocardia several large non-coding regions are present. One of these contains 3.5 nearly identical copies of a 167 bp motive. In Hiatella, the 3' end of the NADH dehydrogenase subunit (nad)6 gene is duplicated together with the adjacent non-coding region. The gene arrangement of Hiatella is markedly different from all other known molluscan mt-genomes, that of Acanthocardia shows few identities with the Venerupis philippinarum. Phylogenetic analyses on amino acid and nucleotide levels robustly support the Heterodonta and the sister group relationship of Acanthocardia and Venerupis. Monophyletic Bivalvia are resolved only by a Bayesian inference of the nucleotide data set. In all other analyses the two unionid species, being to only ones with genes located on both strands, do not group with the remaining bivalves. The two mt-genomes reported here add to and underline the high variability of gene order and presence of duplications in bivalve and molluscan taxa. Some genomic traits like the loss of the atp8 gene or the encoding of all genes on the same strand are homoplastic among the Bivalvia. These characters, gene order, and the nucleotide sequence data show considerable potential of resolving phylogenetic patterns at lower taxonomic levels.