Simková Andrea, Morand Serge, Jobet Edouard, Gelnar Milan, Verneau Olivier
Department of Zoology and Ecology, Faculty of Science, Masaryk University, Kotlárská 2, 61137 Brno, Czech Republic.
Evolution. 2004 May;58(5):1001-18. doi: 10.1111/j.0014-3820.2004.tb00434.x.
Dactylogyrus species (Dactylogyridae: Monogenea) are a group of monogenean gill parasites that are highly specific to freshwater fish of the family Cyprinidae. Dactylogyrus species were sampled from 19 cyprinids and one percid collected in Europe. Using partial 18S rDNA and ITS1 sequences, a phylogeny of 51 Dactylogyrus species was reconstructed to investigate the patterns of parasite speciation and diversification. Three main Dactylogyrus lineages were recognized from all phylogenetic trees, that is, analysis of 18S rDNA alone and combined 18SrDNA and ITS1. The first lineage associates the Dactylogyrus species of Cyprinus carpio and Carassius auratus of the Cyprininae; the second associates Dactylogyrus species of the Gobioninae, Pseudorasbora parva of the Rasborinae, and Ctenopharyngodon idella of the Cyprininae; and the third associates Dactylogyrus species of the Leuciscinae and Alburninae and Barbus barbus of the Cyprininae. Our results suggest that the genus Dactylogyrus is of quite recent origin and that these three lineages separated from each other in a very short period of time. Host subfamily mapping onto the parasite tree inferred from analysis of the combined dataset showed that the Cyprininae could be plesiomorphic hosts for Dactylogyrus. Dactylogyrus parasites would have secondarily colonized the Percidae and representatives of the Leuciscinae, Alburninae, Gobioninae, and Rasborinae. Comparison of host and parasite phylogenetic relationships indicated that a very high number of parasite duplications occurred within two of the three Dactylogyrus lineages. Dactylogyrus diversification can be mainly explained by sympatric intrahost speciation events that seem to be correlated to strict host specificity. Moreover, the present study shows that the congeneric parasites speciating within one host tend to occupy niches within hosts differing at least in one niche parameter.
指环虫属物种（指环虫科：单殖吸虫纲）是一类单殖吸虫鳃寄生虫，对鲤科淡水鱼具有高度特异性。从欧洲采集的19种鲤科鱼类和1种鲈科鱼类中采集了指环虫属物种。利用部分18S核糖体DNA（rDNA）和ITS1序列，重建了51种指环虫属物种的系统发育树，以研究寄生虫物种形成和多样化的模式。从所有系统发育树中识别出三个主要的指环虫谱系，即单独分析18S rDNA以及联合分析18S rDNA和ITS1。第一个谱系将鲤亚科的鲤和鲫的指环虫属物种联系在一起；第二个谱系将鮈亚科的指环虫属物种、波鱼亚科的麦穗鱼以及鲤亚科的草鱼的指环虫属物种联系在一起；第三个谱系将雅罗鱼亚科和赤梢鱼亚科的指环虫属物种以及鲤亚科的鲤的指环虫属物种联系在一起。我们的结果表明，指环虫属起源相当晚，并且这三个谱系在很短的时间内彼此分离。将宿主亚科映射到根据联合数据集分析推断出的寄生虫树上，结果显示鲤亚科可能是指环虫属的原始宿主。指环虫寄生虫可能是后来才定殖到鲈科以及雅罗鱼亚科、赤梢鱼亚科、鮈亚科和波鱼亚科的代表物种上。宿主和寄生虫系统发育关系的比较表明，在三个指环虫谱系中的两个谱系内发生了大量的寄生虫重复事件。指环虫的多样化主要可以通过同域宿主内物种形成事件来解释，这些事件似乎与严格的宿主特异性相关。此外，本研究表明，在一个宿主内形成物种的同属寄生虫倾向于占据至少在一个生态位参数上不同的宿主内生态位。
