Valentini Alice, Mattiucci Simonetta, Bondanelli Paola, Webb Stephen C, Mignucci-Giannone Antonio A, Colom-Llavina Marlene M, Nascetti Giuseppe
Department of Public Health Sciences, Section of Parasitology, University of Rome La Sapienza, 00185 Rome, Italy.
J Parasitol. 2006 Feb;92(1):156-66. doi: 10.1645/GE-3504.1.
The genetic relationships among 9 taxa of Anisakis Dujardin, 1845 (A. simplex (sensu stricto), A. pegreffii, A. simplex C., A. typica, A. ziphidarum, A. physeteris, A. brevispiculata, A. paggiae, and Anisakis sp.) were inferred from sequence analysis (629 bp) of the mitochondrial cox2 gene. Genetic divergence among the considered taxa, estimated by p-distance, ranged from p = 0.055, between sibling species of the A. simplex complex, to p = 0.12, between morphologically differentiated species, i.e., A. ziphidarum and A. typica. The highest level was detected when comparing A. physeteris, A. brevispiculata, and A. paggiae versus A. simplex complex (on average p = 0.13) or versus A. typica (on average p = 0.14). Sequence data from the newly identified Anisakis sp. poorly aligned with other Anisakis species but was most similar to A. ziphidarum (p = 0.08). Phylogenetic analyses based upon Parsimony and Bayesian Inference, as well as phenetic analysis based upon Neighbor-Joining p-distance values, generated similar tree topologies, each well supported at major nodes. All analyses delineated two main claides, the first encompassing A. physeteris, A. brevispiculata, and A. paggiae as a sister group to all the remaining species, and the second comprising the species of the A. simplex complex (A. simplex (s.s.), A. pegreffii and A. simplex C), A. typica, A. ziphidarum, and Anisakis sp. In general, mtDNA-based tree topologies showed high congruence with those generated from nuclear data sets (19 enzyme-loci) and with morphological data delineating adult and larval stages of the Anisakis spp.; however, precise positioning of A. typica and A. ziphidarum remain poorly resolved, though they consistently clustered in the same clade as Anisakis sp. and the A. simplex complex. Comparison of anisakid data with those currently available for their cetacean-definitive hosts suggests parallelism between host and parasite phylogenetic tree topologies.
通过对线粒体细胞色素氧化酶亚基2（cox2）基因进行序列分析（629bp），推断了1845年杜雅尔丹异尖线虫属（Anisakis Dujardin）9个分类单元（简单异尖线虫（狭义）（A. simplex (sensu stricto)）、佩氏异尖线虫（A. pegreffii）、 simplex C型异尖线虫（A. simplex C.）、典型异尖线虫（A. typica）、 齐氏异尖线虫（A. ziphidarum）、 抹香鲸异尖线虫（A. physeteris）、 短刺异尖线虫（A. brevispiculata）、 帕氏异尖线虫（A. paggiae）以及一个未鉴定的异尖线虫物种（Anisakis sp.））之间的亲缘关系。通过p距离估计，所考虑分类单元之间的遗传差异范围为p = 0.055（简单异尖线虫复合种的姊妹种之间）至p = 0.12（形态上有差异的物种之间，即齐氏异尖线虫和典型异尖线虫）。在比较抹香鲸异尖线虫、短刺异尖线虫和帕氏异尖线虫与简单异尖线虫复合种（平均p = 0.13）或与典型异尖线虫（平均p = 0.14）时，检测到最高水平的差异。新鉴定的异尖线虫物种（Anisakis sp.）的序列数据与其他异尖线虫物种的序列数据排列不佳，但与齐氏异尖线虫最为相似（p = 0.08）。基于简约法和贝叶斯推断的系统发育分析，以及基于邻接法p距离值的表型分析，产生了相似的树形拓扑结构，每个主要节点都得到了很好的支持。所有分析都划分出两个主要分支，第一个分支包括抹香鲸异尖线虫、短刺异尖线虫和帕氏异尖线虫，它们是所有其余物种的姊妹群，第二个分支包括简单异尖线虫复合种（狭义简单异尖线虫、佩氏异尖线虫和simplex C型异尖线虫）、典型异尖线虫、齐氏异尖线虫和未鉴定的异尖线虫物种（Anisakis sp.）。一般来说，基于线粒体DNA的树形拓扑结构与从核数据集（19个酶基因座）生成的树形拓扑结构以及描绘异尖线虫属成虫和幼虫阶段的形态学数据高度一致；然而，典型异尖线虫和齐氏异尖线虫的精确定位仍然难以解决，尽管它们始终与未鉴定的异尖线虫物种（Anisakis sp.）和简单异尖线虫复合种聚集在同一分支中。将异尖线虫数据与目前可用于其鲸类终末宿主的数据进行比较，表明宿主和寄生虫系统发育树形拓扑结构之间存在平行关系。
