The long way to diversity - Phylogeny and evolution of the Heterobranchia (Mollusca: Gastropoda)
The long way to diversity - Phylogeny and evolution of the Heterobranchia (Mollusca: Gastropoda)
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DOI：
10.1016/j.ympev.2009.09.019
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发表时间：
2010-04-01
影响因子：
4.1
通讯作者：
Klussmann-Kolb, Annette
中科院分区：
文献类型：
--
作者：
Dinapoli, Angela;Klussmann-Kolb, Annette
异鳃亚纲是腹足纲中物种最丰富的类群之一，其系统发育关系尤其是在基生类群中的关系并未得到很好的解决。为了解决异鳃亚纲内的系统发育关系，我们采用了一种分子系统学方法，对多种遗传标记(包括核28S rDNA+18S rDNA和线粒体16S rDNA+COI序列)进行了测序和分析。系统发育重建采用最大似然法和贝叶斯推理法。此外，为了证明新的系统发育假说的真实性，使用了各种统计检验和网络分析，对数据质量进行了评估。最后，进行了一个案例研究，以化石为最小年龄限制，采用“松弛的”分子钟方法来估算分化年龄。所有的系统发育分析都表明，异鳃亚纲是单系进化的。在异布兰科内部，几个得到很好支持的支系可以被解决。然而，基于形态数据的传统分类由于甲状旁腺神经元以及甲状旁腺肺瘤和多系视支的存在而不能被证实。数据质量的估计在许多核苷酸位置产生了高度的替代饱和度，而相对速率检验显示在“下异支臂”内的进化速率最高。尽管数据集显示出许多矛盾之处，但许多提出的假说都得到了网络分析的分裂的支持。分子时钟方法能够证实一些基于化石的进化假说，例如中生代分别出现肺门类和柱头类的晚期。然而，一些节点上95%的最高后验密度(HPD)间隔很大，这使得准确测定这些节点的年龄变得困难。这一分子系统发育研究提供了迄今为止最全面的异支气管内关系的分子研究。由于在早期的形态和分子研究中缺乏代表性的“下异叉”分类单元样本，人们对这一神秘分类单元的进化和系统发育有了很大的了解。(C)2009 Elsevier Inc.保留所有权利。
Heterobranchia are one of the most species rich groups within Gastropoda, with poorly resolved phylogenetic relationships especially in basal taxa. In order to resolve phylogenetic relationships within the Heterobranchia, we pursued a molecular systematic approach by sequencing and analysing a variety of genetic markers (including nuclear 28S rDNA + 18S rDNA and mitochondrial 16S rDNA + COI sequences). Maximum likelihood as well as Bayesian inference methods were used for phylogenetic reconstruction. Moreover, data quality was estimated for the purpose of proving the plausibility of the novel phylogenetic hypothesis using a variety of statistical tests as well as network analyses. Finally, a case study was conducted in order to estimate divergence ages using a "relaxed" molecular clock approach with fossils as minimum age constraints.All phylogenetic analyses revealed the Heterobranchia as monophyletic. Within the Heterobranchia, several well supported clades could be resolved. However, the traditional classification based on morphological data could not be confirmed due to paraphyletic Euthyneura as well as paraphyletic Pulmonata and polyphyletic Opisthobranchia.The estimation of data quality yielded a high degree of substitution saturation in many of the nucleotide positions while the Relative-Rate-Test revealed the highest evolution rates within the "Lower Heterobranchia". Although the dataset shows much conflict, many of the proposed hypotheses are supported by splits of the network analysis.The molecular clock approach was able to confirm some evolutionary hypotheses based on fossils such as the late occurrence of Pulmonata and Stylommatophora, respectively, during the Mesozoic. However, large 95% highest posterior density (HPD) intervals at some of the nodes made a precise dating of these nodes difficult.This molecular phylogenetic investigation provides the most comprehensive molecular study of relationships within the Heterobranchia to date. Due to the outstanding taxon sampling of the "Lower Heterobranchia", which have been poorly represented in earlier morphological and molecular studies, substantial insights into the evolution and phylogeny of this enigmatic taxon have been gained. (C) 2009 Elsevier Inc. All rights reserved.