Catania Francesco, Wurmser François, Potekhin Alexey A, Przybos Ewa, Lynch Michael
Department of Biology, Indiana University, USA.
Mol Biol Evol. 2009 Feb;26(2):421-31. doi: 10.1093/molbev/msn266. Epub 2008 Nov 20.
Current understanding of the population genetics of free-living unicellular eukaryotes is limited, and the amount of genetic variability in these organisms is still a matter of debate. We characterized-reproductively and genetically-worldwide samples of multiple Paramecium species belonging to a cryptic species complex, Paramecium aurelia, whose species have been shown to be reproductively isolated. We found that levels of genetic diversity both in the nucleus and in the mitochondrion are substantial within groups of reproductively compatible P. aurelia strains but drop considerably when strains are partitioned according to their phylogenetic groupings. Our study reveals the existence of discrepancies between the mating behavior of a number of P. aurelia strains and their multilocus genetic profile, a controversial finding that has major consequences for both the current methods of species assignment and the species problem in the P. aurelia complex.
目前对自由生活的单细胞真核生物群体遗传学的理解有限，这些生物的遗传变异性数量仍是一个有争议的问题。我们对属于一个隐性物种复合体——草履虫（Paramecium aurelia）的多个草履虫物种进行了全球范围的生殖和遗传特征分析，该复合体中的物种已被证明存在生殖隔离。我们发现，在生殖相容的草履虫菌株组内，细胞核和线粒体中的遗传多样性水平都很高，但当根据系统发育分组对菌株进行划分时，遗传多样性水平会大幅下降。我们的研究揭示了一些草履虫菌株的交配行为与其多位点遗传图谱之间存在差异，这一有争议的发现对当前的物种分类方法以及草履虫复合体中的物种问题都有重大影响。
