Shen Xin, Tsang Ling Ming, Chu Ka Hou, Achituv Yair, Chan Benny Kwok Kan
Jiangsu Key Laboratory of Marine Biotechnology/College of Marine Science/Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Huaihai Institute of Technology, Lianyungang 222005, China; Simon F. S. Li Marine Science Laboratory, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Institute of Marine Biology, National Taiwan Ocean University, Keelung 202, Taiwan.
Mar Genomics. 2015 Aug;22:63-9. doi: 10.1016/j.margen.2015.04.004. Epub 2015 Apr 20.
The complete mitochondrial genome of the intertidal barnacle Tetraclita serrata Darwin, 1854 (Crustacea: Maxillopoda: Sessilia) is presented. The genome is a circular molecule of 15,200 bp, which encodes 13 PCGs, 2 ribosomal RNA genes, and 22 transfer RNA genes. All non-coding regions are 591 bp in length, with the longest one speculated as the control region (389 bp), which is located between srRNA and trnK. The overall A+T content of the mitochondrial genome of T. serrata is 65.4%, which is lowest among all the eight mitochondrial genomes reported from sessile barnacles. There are variations of initiation and stop codons in the reported sessile barnacle mitochondrial genomes. Large-scale gene rearrangements are found in these genomes as compared to the pancrustacean ground pattern. ML and Bayesian analyses of all 15 complete mitochondrial genomes available from Maxillopoda lead to identical phylogenies. The phylogenetic tree based on mitochondrial PCGs shows that Argulus americanus (Branchiura) cluster with Armillifer armillatus (Pentastomida), distinct from all ten species from Cirripedia. Within the order Sessilia, Amphibalanus amphitrite (Balanidae) clusters with Striatobalanus amaryllis (Archaeobalanidae), and Nobia grandis (Pyrgomatidae). However, the two Megabalanus (Balanidae) are separated from the above grouping, resulting in non-monophyly of the family Balanidae. Moreover, the two Megabalanus have large-scale rearrangements as compared to the gene order shared by former three species. Therefore, both phylogenetic analysis using PCG sequences and gene order comparison suggest that Balanidae is not a monophyletic group. Given the limited taxa and moderate support values of the internal branches, the non-monophyly of the family Balanidae requires further verification.
本文报道了潮间带藤壶四齿小藤壶（Tetraclita serrata Darwin，1854）（甲壳纲：颚足纲：无柄目）的完整线粒体基因组。该基因组是一个15,200 bp的环状分子，编码13个蛋白质编码基因（PCGs）、2个核糖体RNA基因和22个转运RNA基因。所有非编码区长度均为591 bp，最长的一个推测为控制区（389 bp），位于srRNA和trnK之间。四齿小藤壶线粒体基因组的总体A+T含量为65.4%，是已报道的所有八种固着藤壶线粒体基因组中最低的。在已报道的固着藤壶线粒体基因组中，起始密码子和终止密码子存在变异。与泛甲壳动物的基本模式相比，这些基因组中发现了大规模的基因重排。对颚足纲现有的15个完整线粒体基因组进行最大似然法（ML）和贝叶斯分析，得到了相同的系统发育树。基于线粒体PCGs的系统发育树表明，美洲鲺（Branchiura）与有沟臂尾线虫（Pentastomida）聚类，与所有十种蔓足亚纲物种不同。在无柄目内，纹藤壶（Balanidae）与红纹条藤壶（Archaeobalanidae）和大瘤藤壶（Pyrgomatidae）聚类。然而，两种巨藤壶（Balanidae）与上述聚类分开，导致藤壶科不是单系类群。此外，与前三个物种共享的基因顺序相比，两种巨藤壶有大规模的重排。因此，使用PCG序列的系统发育分析和基因顺序比较都表明藤壶科不是一个单系类群。鉴于分类单元有限且内部分支的支持值适中，藤壶科的非单系性需要进一步验证。
