Mattiucci Simonetta, Nascetti Giuseppe
Department of Public Health Sciences, Section of Parasitology, Sapienza-University of Rome, P.le Aldo Moro, 5, 00185 Rome, Italy.
Adv Parasitol. 2008;66:47-148. doi: 10.1016/S0065-308X(08)00202-9.
The application of molecular systematics to the anisakid nematodes of the genera Anisakis, Pseudoterranova and Contracaecum, parasites of aquatic organisms, over the last two decades, has advanced the understanding of their systematics, taxonomy, ecology and phylogeny substantially. Here the results of this effort on this group of species from the early genetic works to the current status of their revised taxonomy, ecology and evolutionary aspects are reviewed for each of three parasitic groups. It has been shown that many anisakid morphospecies of Anisakis, Contracaecum and Pseudoterranova include a certain number of sibling species. Molecular genetic markers provided a rapid, precise means to screen and identify several species that serve as definitive and intermediate and or/paratenic hosts of the so far genetically characterized species. Patterns of differential distribution of anisakid nematodes in various definitive and intermediate hosts are presented. Differences in the life history of related species can be due both to differential host-parasite co-adaptation and co-evolution, and/or to interspecific competition, that can reduce the range of potential hosts in sympatric conditions. Phylogenetic hypotheses attempted for anisakid nematodes and the possible evolutionary scenarios that have been proposed inferred from molecular data, also with respect to the phylogeny of their hosts are presented for the parasite-host associations Anisakis-cetaceans and Contracaecum-pinnipeds, showing that codivergence and host-switching events could have accompanied the evolution of these groups of parasites. Finally, examples in which anisakid nematodes recognized genetically at the species level in definitive and intermediate/paratenic hosts from various geographical areas of the Boreal and Austral regions and their infection levels have been used as biological indicators of fish stocks and food-web integrity in areas at high versus low levels of habitat disturbance (pollution, overfishing, by-catch) are presented.
在过去二十年中，分子系统学应用于海洋生物寄生虫——异尖线虫属（Anisakis）、拟新地蛔线虫属（Pseudoterranova）和对盲囊线虫属（Contracaecum）的线虫研究，极大地推动了对它们的系统学、分类学、生态学和系统发育的理解。本文针对这三类寄生虫，综述了从早期基因研究到其修订分类学、生态学和进化方面的现状等一系列研究成果。研究表明，异尖线虫属、对盲囊线虫属和拟新地蛔线虫属的许多形态物种包含一定数量的姊妹种。分子遗传标记提供了一种快速、精确的手段，用于筛选和识别作为目前已进行基因特征分析物种的终末宿主、中间宿主和/或转续宿主的若干物种。文中展示了异尖线虫在各种终末宿主和中间宿主中的差异分布模式。相关物种生活史的差异可能是由于宿主 - 寄生虫的协同适应和协同进化，和/或种间竞争，这可能会缩小同域条件下潜在宿主的范围。本文还介绍了针对异尖线虫的系统发育假说，以及根据分子数据提出的可能进化场景，同样涉及它们宿主的系统发育，展示了共分化和宿主转换事件可能伴随这些寄生虫群体的进化。最后，列举了一些实例，在这些实例中，来自北方和南方地区不同地理区域的终末宿主以及中间/转续宿主中，在物种水平上通过基因识别的异尖线虫及其感染水平，被用作高栖息地干扰（污染、过度捕捞、兼捕）与低栖息地干扰地区鱼类资源和食物网完整性的生物学指标。
