Lefoulon Emilie, Giannelli Alessio, Makepeace Benjamin L, Mutafchiev Yasen, Townson Simon, Uni Shigehiko, Verocai Guilherme G, Otranto Domenico, Martin Coralie
Unité Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Sorbonne Universités, Muséum National d'Histoire Naturelle, CNRS, Paris, France.
Department of Veterinary Medicine, Università degli Studi di Bari, Valenzano, Italy.
Int J Parasitol. 2017 Jul;47(8):457-470. doi: 10.1016/j.ijpara.2016.12.009. Epub 2017 Mar 24.
The genus Onchocerca includes 34 described species and represents one of the largest genera of the filarial nematodes within the family Onchocercidae. Representative members of this genus are mainly parasites of ungulates, with some exceptions such as Onchocerca lupi and Onchocerca volvulus, infecting carnivores and/or humans. For a long time, the evolutionary relationships amongst onchocercids remained poorly studied, as the systematics of this genus was impaired by the high morphological variability of species included in the taxon. Although some molecular phylogenies were developed, these studies were mainly focused on bovine Onchocerca spp. and O. volvulus, including assessments of Wolbachia endosymbionts. In the present study, we analysed 13 Onchocerca spp. from a larger host spectrum using a panel of seven different genes. Analysis of the coxI marker supports its usefulness for the identification of species within the genus. The evolutionary history of the genus has been herein revised by multi-gene phylogenies, presenting three strongly supported clades of Onchocerca spp. Analyses of co-evolutionary scenarios between Onchocerca and their vertebrate hosts underline the effect of domestication on Onchocerca speciation. Our study indicates that a host switch event occurred between Bovidae, Canidae and humans. Cophylogenetic analyses between Onchocerca and the endosymbiotic bacterium Wolbachia indicate the strongest co-evolutionary pattern ever registered within the filarial nematodes. Finally, this dataset indicates that the clade composed by O. lupi, Onchocerca gutturosa, Onchocerca lienalis, Onchocerca ochengi and O. volvulus derived from recent speciation.
盘尾丝虫属包含34个已描述的物种，是盘尾丝虫科内最大的丝虫线虫属之一。该属的代表性成员主要是有蹄类动物的寄生虫，但也有一些例外，如狼盘尾丝虫和旋盘尾丝虫，可感染食肉动物和/或人类。长期以来，盘尾丝虫科之间的进化关系研究甚少，因为该属的系统分类受到分类群中物种高度形态变异性的影响。尽管开展了一些分子系统发育研究，但这些研究主要集中在牛盘尾丝虫属物种和旋盘尾丝虫，包括对沃尔巴克氏体共生菌的评估。在本研究中，我们使用一组七个不同的基因，分析了来自更广泛宿主谱的13种盘尾丝虫属物种。细胞色素氧化酶亚基I（coxI）标记的分析支持了其在盘尾丝虫属物种鉴定中的实用性。通过多基因系统发育，本研究修订了该属的进化历史，呈现出三个得到有力支持的盘尾丝虫属物种分支。盘尾丝虫与其脊椎动物宿主之间的共进化情景分析强调了驯化对盘尾丝虫物种形成的影响。我们的研究表明，在牛科、犬科和人类之间发生了宿主转换事件。盘尾丝虫与内共生细菌沃尔巴克氏体之间的共系统发育分析表明，这是丝虫线虫中记录到的最强共进化模式。最后，该数据集表明，由狼盘尾丝虫、喉盘尾丝虫、肠系膜盘尾丝虫、奥氏盘尾丝虫和旋盘尾丝虫组成的分支源自近期的物种形成。
