Phylogenetic relationships within Echinococcus and Taenia tapeworms (Cestoda: Taeniidae): An inference from nuclear protein-coding genes
Phylogenetic relationships within Echinococcus and Taenia tapeworms (Cestoda: Taeniidae): An inference from nuclear protein-coding genes
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DOI：
10.1016/j.ympev.2011.07.022
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发表时间：
2011-12-01
影响因子：
4.1
通讯作者：
Ito, Akira
中科院分区：
文献类型：
--
作者：
Knapp, Jenny;Nakao, Minoru;Ito, Akira
带绦虫科由棘球绦虫和带绦虫两个属组成，它们专性寄生于包括人类在内的哺乳动物。通过分子标记推断系统发育是追溯它们进化史的唯一途径。然而，到目前为止，还缺乏分子测年方法。在这里，我们从核蛋白编码基因中建立了RNA聚合酶II第二大亚基(Rpb2)、磷酸烯醇式丙酮酸羧激酶(PEPCK)和DNA聚合酶增量(Pold)的新标记。连接的基因序列的贝叶斯推断和最大似然分析使我们能够重建带绦虫的系统发育树。树状拓扑结构清楚地表明，带绦虫是副反应性的，少节棘球绦虫和沃格利棘球绦虫的分支与棘球绦虫的所有其他成员是姐妹。这两个物种都是中美洲和南美洲特有的物种，它们的最终宿主来自大约300万年前巴拿马大陆桥形成后从北美移民的食肉动物。利用贝叶斯松弛时钟方法，基于上新世晚期(3.0 Ma)存在寡齿棘豆和沃格利的最新共同祖先的假设，估计了时间刻度的系统发育。结果表明，包括人类致病种在内的一支带绦虫主要在中新世晚期(11.2 Ma)发生多样性，而棘球绦虫在中新世末期(5.8 Ma)开始出现多样性。棘球绦虫成员间亲缘关系密切，表明该属是一个物种形成和全球辐射迅速发生的年轻群体。(C)2011 Elsevier Inc.保留所有权利。
The family Taeniidae of tapeworms is composed of two genera, Echinococcus and Taenia, which obligately parasitize mammals including humans. Inferring phylogeny via molecular markers is the only way to trace back their evolutionary histories. However, molecular dating approaches are lacking so far. Here we established new markers from nuclear protein-coding genes for RNA polymerase II second largest subunit (rpb2), phosphoenolpyruvate carboxykinase (pepck) and DNA polymerase delta (pold). Bayesian inference and maximum likelihood analyses of the concatenated gene sequences allowed us to reconstruct phylogenetic trees for taeniid parasites. The tree topologies clearly demonstrated that Taenia is paraphyletic and that the clade of Echinococcus oligarthrus and Echinococcus vogeli is sister to all other members of Echinococcus. Both species are endemic in Central and South America, and their definitive hosts originated from carnivores that immigrated from North America after the formation of the Panamanian land bridge about 3 million years ago (Ma). A time-calibrated phylogeny was estimated by a Bayesian relaxed-clock method based on the assumption that the most recent common ancestor of E. oligarthrus and E. vogeli existed during the late Pliocene (3.0 Ma). The results suggest that a clade of Taenia including human-pathogenic species diversified primarily in the late Miocene (11.2 Ma), whereas Echinococcus started to diversify later, in the end of the Miocene (5.8 Ma). Close genetic relationships among the members of Echinococcus imply that the genus is a young group in which speciation and global radiation occurred rapidly. (C) 2011 Elsevier Inc. All rights reserved.