Fox Martin G, Sorhannus Ulf M
Department of Biology and Health Services, Edinboro University of Pennsylvania, Edinboro, Pennsylvania 16444, USA.
J Eukaryot Microbiol. 2003 Nov-Dec;50(6):471-5. doi: 10.1111/j.1550-7408.2003.tb00273.x.
The aim of this study was to compare the usefulness of two chloroplast-encoded genes (rpoA and rbcL) and the nuclear-encoded small subunit (SSU) ribosomal RNA for reconstructing phylogenetic relationships among diatoms at lower taxonomic levels. To this end, the rpoA and rbcL genes for selected centric and pennate diatoms were sequenced. The new rpoA and rbcL sequences, and an existing nuclear-encoded SSU rRNA data set, were subjected to weighted/unweighted parsimony, maximum likelihood, minimum evolution, and Bayesian analyses. All of the tree-building methods employed showed, based on the support values, that the rpoA gene was the most useful, relative to the rbcL and SSU rRNA genes, in determining phylogenetic relationships among the sampled diatoms. The support values for the relationships among the pennate lineages were, in many instances, greater in the rpoA trees than in the SSU rRNA trees. These results suggest that rpoA might be of value in determining phylogenetic relationships among pennate lineages.
本研究的目的是比较两个叶绿体编码基因（rpoA和rbcL）以及核编码小亚基（SSU）核糖体RNA在重建硅藻较低分类水平系统发育关系方面的有用性。为此，对选定的中心硅藻和羽纹硅藻的rpoA和rbcL基因进行了测序。新的rpoA和rbcL序列以及现有的核编码SSU rRNA数据集进行了加权/非加权简约法、最大似然法、最小进化法和贝叶斯分析。基于支持值，所有采用的建树方法均表明，相对于rbcL和SSU rRNA基因，rpoA基因在确定采样硅藻的系统发育关系方面最有用。在许多情况下，羽纹谱系之间关系的支持值在rpoA树中比在SSU rRNA树中更高。这些结果表明，rpoA在确定羽纹谱系之间的系统发育关系方面可能具有价值。
