von Nickisch-Rosenegk M, Lucius R, Loos-Frank B
Humboldt-Universität zu Berlin, Lehrstuhl für Molekulare Parasitologie (Institut für Biologie), Philippstr. 13, 10115 Berlin, Germany.
J Mol Evol. 1999 May;48(5):586-96. doi: 10.1007/pl00006501.
A 314-bp fragment of the mitochondrial 12S rRNA gene from 21 cestodes species of eight families was synthesized by PCR with specially designed primers. These allowed amplification of parasite DNA without concomitant synthesis of host DNA. Phylogenetic trees were inferred from the sequence data using three methods (maximum parsimony, maximum likelihood, and Fitch-Margoliash). At the major nodes all three trees were similar. For the first time the genus Mesocestoides could be arranged into the Cyclophyllidea and a narrow relationship between the Mesocestoididae, Taeniidae, Hymenolepididae, Anoplocephalidae, and Dipylidiidae was shown. Members of the families Catenotaeniidae and a cluster of two families (Hymenolepididae and Dilepididae) form two monophyletic groups which derive prior to the remaining families of this phylogenetic study. A third and a fourth clear monophyletic group were formed by the Taeniidae and by the Mesocestoididae. A high degree of variation within the examined 304-bp fragment was observed between two isolates of Taenia taeniaeformis, supporting often discussed genetic heterogeneity within this species. In contrast, only one nucleotide exchange was found in 23 isolates of Echinococcus multilocularis of various geographic origin, indicating that this species is genetically homogenous.
利用特别设计的引物通过聚合酶链反应（PCR）合成了来自8个科21种绦虫线粒体12S rRNA基因的314碱基对片段。这些引物能够扩增寄生虫DNA，而不会同时合成宿主DNA。使用三种方法（最大简约法、最大似然法和菲奇-马戈利亚什法）从序列数据推断系统发育树。在主要节点处，所有三棵树都相似。首次将中殖孔绦虫属归入圆叶目，并显示了中殖孔绦虫科、带科、膜壳科、无钩绦虫科和双叶槽绦虫科之间的密切关系。链尾绦虫科的成员以及两个科（膜壳科和双壳科）的一个聚类形成了两个单系类群，它们在该系统发育研究的其余科之前分化出来。第三个和第四个明确的单系类群分别由带科和中殖孔绦虫科形成。在泡状带绦虫的两个分离株之间，在所检测的304碱基对片段中观察到高度变异，支持了该物种内经常讨论的遗传异质性。相比之下，在来自不同地理来源的23个多房棘球绦虫分离株中仅发现一个核苷酸交换，表明该物种在遗传上是同质的。
