Dipartimento di Biologia, Unità di Protistologia-Zoologia, Università di Pisa, Via A. Volta 4, 56126 Pisa, Italy.
Mol Phylogenet Evol. 2012 Dec;65(3):1004-13. doi: 10.1016/j.ympev.2012.09.001. Epub 2012 Sep 13.
The genus Paramecium (phylum Ciliophora) is one of the best-known among protozoa. Nevertheless, the knowledge on the diversity and distribution of species within this genus was remarkably scarce until recent times. In the last years a constantly growing amount of data has formed, especially on the distribution of species and the characterization of molecular markers. Much effort has been made on detecting clades inside each morphospecies, which could suggest the presence of sibling species complexes as in the famous case of Paramecium aurelia. In this work we present new data on Paramecium duboscqui, one of the morphospecies that have not yet been surveyed employing DNA sequences as markers. We obtained data from nine strains sampled around the world, using the three most commonly employed markers (18S rRNA gene, ITS1-5.8S-ITS2 and COI gene sequences). Moreover, we compared our results with those already available for other Paramecium species, and performed phylogenetic analyses for the entire genus. We also expanded the knowledge on the ITS2 secondary structure and its usefulness in studies on Paramecium. Our approach, that considers the data of all the species together, highlighted some characteristic patterns as well as some ambiguities that should be further investigated.
类 Paramecium（纤毛门）是原生动物中最为人熟知的属之一。然而，直到最近，人们对该属内物种的多样性和分布的了解还非常有限。在过去的几年中，形成了大量不断增长的数据，特别是关于物种的分布和分子标记的特征。人们已经做出了很大的努力来检测每个形态种内的进化枝，这可能表明存在像著名的 Paramecium aurelia 那样的姐妹种复合体。在这项工作中，我们介绍了尚未采用 DNA 序列作为标记进行调查的形态种之一 Paramecium duboscqui 的新数据。我们使用最常用的三个标记（18S rRNA 基因、ITS1-5.8S-ITS2 和 COI 基因序列），从全球范围内采集的九个品系中获得了数据。此外，我们将我们的结果与其他 Paramecium 物种的已有数据进行了比较，并对整个属进行了系统发育分析。我们还扩展了关于 ITS2 二级结构及其在 Paramecium 研究中的有用性的知识。我们的方法考虑了所有物种的数据，突出了一些特征模式以及一些应该进一步研究的模糊性。
