Department of Ecology, University of Kaiserslautern, Germany.
Eur J Protistol. 2012 Nov;48(4):297-304. doi: 10.1016/j.ejop.2012.01.007. Epub 2012 Feb 20.
Our understanding of the evolution of oral structures within the Colpodida is confounded by the low number of morphological characters that can be used in constructing hypotheses, and by the low taxon and character sampling in molecular phylogenetic analyses designed to assess these hypotheses. Here we increase character sampling by sequencing the mitochondrial SSU-rDNA locus for three isolates of the Marynidae sensu lato. We show that the inferred mitochondrial and nuclear SSU-rDNA trees, as well as concatenated and constrained analyses, are congruent in not recovering a monophyletic Marynidae. However, due to low node support, the trees are indifferent to whether the morphological characters used to unite the Marynidae are the result of retention of ancestral states or convergence. In light of this indifference and an increased amount of nuclear and mitochondrial SSU-rDNA data, alternative hypotheses of oral evolution in the Colpodida are presented.
我们对 Colpodida 中口腔结构进化的理解受到以下因素的阻碍：可用作假设构建的形态特征数量较少，以及用于评估这些假设的分子系统发育分析中的分类群和特征采样较少。在这里，我们通过对广义玛丽娜科的三个分离株进行线粒体 SSU-rDNA 基因座测序，增加了特征采样。我们表明，推断的线粒体和核 SSU-rDNA 树，以及串联和约束分析，在不恢复玛丽娜科单系性方面是一致的。然而，由于节点支持率低，这些树对于将玛丽娜科联合在一起的形态特征是由于祖先状态的保留还是趋同，并没有明显的偏向。鉴于这种不偏向性以及更多的核和线粒体 SSU-rDNA 数据，提出了 Colpodida 中口腔进化的替代假说。
