核编码的小亚基核糖体DNA在解析硅藻系统发育中的局限性。

The limits of nuclear encoded SSU rDNA for resolving the diatom phylogeny.

作者信息

Theriot Edward C, Cannone Jamie J, Gutell Robin R, Alverson Andrew J

机构信息

Texas Natural Science Center, 2400 Trinity Street, The University of Texas at Austin, Austin, TX 78705, USA.

出版信息

Eur J Phycol. 2009 Aug 1;44(3):277-290. doi: 10.1080/09670260902749159.

A recent reclassification of diatoms based on phylogenies recovered using the nuclear-encoded SSU rRNA gene contains three major classes, Coscinodiscophyceae, Mediophyceae and the Bacillariophyceae (the CMB hypothesis). We evaluated this with a sequence alignment of 1336 protist and heterokont algae SSU rRNAs, which includes 673 diatoms. Sequences were aligned to maintain structural elements conserved within this dataset. Parsimony analysis rejected the CMB hypothesis, albeit weakly. Morphological data are also incongruent with this recent CMB hypothesis of three diatom clades. We also reanalyzed a recently published dataset which purports to support the CMB hypothesis. Our reanalysis found that the original analysis had not converged on the true bipartition posterior probability distribution, and rejected the CMB hypothesis. Thus we conclude that a reclassification of the evolutionary relationships of the diatoms according to the CMB hypothesis is premature.

最近基于使用核编码的小亚基核糖体RNA基因恢复的系统发育对硅藻进行的重新分类包含三个主要类群，圆筛藻纲、中肋骨条藻纲和硅藻纲（CMB假说）。我们用1336个原生生物和不等鞭毛藻类小亚基核糖体RNA的序列比对对此进行了评估，其中包括673个硅藻。序列比对是为了保持该数据集中保守的结构元件。简约分析拒绝了CMB假说，尽管力度较弱。形态学数据也与最近关于三个硅藻进化枝的CMB假说不一致。我们还重新分析了最近发表的一个声称支持CMB假说的数据集。我们的重新分析发现，原来的分析没有收敛到真正的二分后验概率分布，并拒绝了CMB假说。因此我们得出结论，根据CMB假说对硅藻进化关系进行重新分类还为时过早。