Nearly Complete 28S rRNA Gene Sequences Confirm New Hypotheses of Sponge Evolution
Nearly Complete 28S rRNA Gene Sequences Confirm New Hypotheses of Sponge Evolution
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DOI：
10.1093/icb/ict071
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发表时间：
2013-09-01
影响因子：
2.6
通讯作者：
Bangalore, Purushotham V.
中科院分区：
文献类型：
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作者：
Thacker, Robert W.;Hill, April L.;Bangalore, Purushotham V.
这项由NSF资助的组装Porifera生命树(Portol)项目赞助的高度合作的研究为后生动物系统学中的一些最困难的问题提供了见解。随着分类单元样本的增加和来自更多分子标记的数据的增加，我们对Porifera门内的系统发育关系的理解已经发生了很大的变化。Portol的研究人员证伪了早期的系统发育假说，发现了新的系统发育联盟，发现了神秘分类群的系统发育家园，并对骨骼特征、次生代谢物、身体组织和共生的进化提供了更准确的理解。其中一些令人兴奋的新发现被分享在形成本期《综合与比较生物学》的论文中。我们对300多个几乎完整的28S核糖体亚基基因序列的分析提供了具体的案例研究，说明了我们的数据集如何证实了海绵进化的新假设。我们恢复了所有4类海绵的单系支系，以及蠕形藻亚科的4个主要支系(角化、粘液寄生、单裂形目和异裂形目)，但我们的系统发育在几个方面与传统的分类不同。在大多数主要的海绵支系中，目内的家庭似乎是异体的。尽管需要额外的基因和分类样本来确定这种模式是由于缺乏系统发育分辨率还是来自副系分类系统，但我们的许多结果与从18S核糖体亚单位基因序列和完整线粒体基因组获得的结果是一致的。这些数据为修订传统的海绵分类提供了进一步的支持。
The highly collaborative research sponsored by the NSF-funded Assembling the Porifera Tree of Life (PorToL) project is providing insights into some of the most difficult questions in metazoan systematics. Our understanding of phylogenetic relationships within the phylum Porifera has changed considerably with increased taxon sampling and data from additional molecular markers. PorToL researchers have falsified earlier phylogenetic hypotheses, discovered novel phylogenetic alliances, found phylogenetic homes for enigmatic taxa, and provided a more precise understanding of the evolution of skeletal features, secondary metabolites, body organization, and symbioses. Some of these exciting new discoveries are shared in the papers that form this issue of Integrative and Comparative Biology. Our analyses of over 300 nearly complete 28S ribosomal subunit gene sequences provide specific case studies that illustrate how our dataset confirms new hypotheses of sponge evolution. We recovered monophyletic clades for all 4 classes of sponges, as well as the 4 major clades of Demospongiae (Keratosa, Myxospongiae, Haploscleromorpha, and Heteroscleromorpha), but our phylogeny differs in several aspects from traditional classifications. In most major clades of sponges, families within orders appear to be paraphyletic. Although additional sampling of genes and taxa are needed to establish whether this pattern results from a lack of phylogenetic resolution or from a paraphyletic classification system, many of our results are congruent with those obtained from 18S ribosomal subunit gene sequences and complete mitochondrial genomes. These data provide further support for a revision of the traditional classification of sponges.