Phylogenetic analysis of higher-level relationships within Hydroidolina (Cnidaria: Hydrozoa) using mitochondrial genome data and insight into their mitochondrial transcription.
Phylogenetic analysis of higher-level relationships within Hydroidolina (Cnidaria: Hydrozoa) using mitochondrial genome data and insight into their mitochondrial transcription.
复制标题
使用线粒体基因组数据以及对线粒体转录的洞察力，对氢化烷（Cnidaria：hydrozoa）内高级关系的系统发育分析。
作者：
Kayal E;Bentlage B;Cartwright P;Yanagihara AA;Lindsay DJ;Hopcroft RR;Collins AG
水螅水母类在刺胞动物门中展现出最大的形态多样性。虽然近期的分子研究对其进化历史提供了一些见解，但姐妹群关系大多仍未解决，特别是在中级分类水平上。具体而言，在水螅水母亚纲（水螅水母类中物种最丰富的亚纲）内，目的关系以及有时目的完整性极不稳定。在此，我们从一系列来源（DNA和RNA测序数据、长距离PCR）获得了26种水螅水母亚纲水螅水母物种近乎完整的线粒体序列。我们的分析证实了先前对水螅水母类线粒体DNA进化的推断，同时引入了一种新的基因组结构。利用RNA测序数据，我们提出了水螅水母亚纲中线粒体mRNA表达的一种机制，该机制可外推到其他钵水母类群。利用全套线粒体基因序列进行的系统发育分析对水螅水母亚纲内的目级关系提供了一些见解，包括管水母目作为最先分化出的分支，一个由软水母目 - 丝螅目III - IV组成的有充分支持的分支，以及一个由无浮浪幼虫亚目 - 狭义的头螅目 - 丝螅目I - II组成的第二个分支。最后，我们描述了我们相对廉价且易于获取的多重扩增策略，用于对长距离PCR扩增子进行测序，该策略可适用于大多数高通量测序平台。
Hydrozoans display the most morphological diversity within the phylum Cnidaria. While recent molecular studies have provided some insights into their evolutionary history, sister group relationships remain mostly unresolved, particularly at mid-taxonomic levels. Specifically, within Hydroidolina, the most speciose hydrozoan subclass, the relationships and sometimes integrity of orders are highly unsettled. Here we obtained the near complete mitochondrial sequence of twenty-six hydroidolinan hydrozoan species from a range of sources (DNA and RNA-seq data, long-range PCR). Our analyses confirm previous inference of the evolution of mtDNA in Hydrozoa while introducing a novel genome organization. Using RNA-seq data, we propose a mechanism for the expression of mitochondrial mRNA in Hydroidolina that can be extrapolated to the other medusozoan taxa. Phylogenetic analyses using the full set of mitochondrial gene sequences provide some insights into the order-level relationships within Hydroidolina, including siphonophores as the first diverging clade, a well-supported clade comprised of Leptothecata-Filifera III–IV, and a second clade comprised of Aplanulata-Capitata s.s.-Filifera I–II. Finally, we describe our relatively inexpensive and accessible multiplexing strategy to sequence long-range PCR amplicons that can be adapted to most high-throughput sequencing platforms.