Després L, Kruger F J, Imbert-Establet D, Adamson M L
Laboratoire de Biologie des Populations d'Altitude, CNRS URA 1946 Université J. Fourier, Grenoble, France.
Int J Parasitol. 1995 Dec;25(12):1509-14. doi: 10.1016/0020-7519(95)00048-8.
The internal transcribed spacer region of the ribosomal RNA, ITS2, was sequenced from a single specimen of S. hippopotami collected from a pulmonary artery of the hippopotamus, Hippopotamus amphibius in South Africa. The nucleotide sequence was aligned with those of S. mansoni, S. rodhaini, S. haematobium, S. intercalatum, S. curassoni, S. bovis and S. japonicum. Both maximum parsimony and genetic distance analyses were performed on these data sets. Using S. japonicum as outgroup to the African schistosomes, a single most-parasmonious tree was obtained of length 64 steps with a consistency index of 1-S. hippopotami was the sister-group to the remaining African species. This species has lateral-spined eggs and its basal position in the tree suggests that this condition is primitive and that terminal-spined eggs developed secondarily. Molecular data clearly show that S. hippopotami cannot be considered synonymous with S. mansoni. Assuming the hippopotamus is the normal host of S. hippopotami, phylogenetic analysis is consistent with an ancient association between schistosomes and ungulates.
从南非一只河马（Hippopotamus amphibius）肺动脉采集的单只河马血吸虫（Schistosoma hippopotami）标本中，对核糖体RNA的内部转录间隔区ITS2进行了测序。将该核苷酸序列与曼氏血吸虫（S. mansoni）、罗氏血吸虫（S. rodhaini）、埃及血吸虫（S. haematobium）、间插血吸虫（S. intercalatum）、库氏血吸虫（S. curassoni）、牛血吸虫（S. bovis）和日本血吸虫（S. japonicum）的序列进行比对。对这些数据集进行了最大简约法和遗传距离分析。以日本血吸虫作为非洲血吸虫的外类群，得到了一棵单一的最简约树，长度为64步，一致性指数为1。河马血吸虫是其余非洲物种的姐妹群。该物种有侧棘卵，其在树中的基部位置表明这种情况是原始的，而端棘卵是次生发育而来的。分子数据清楚地表明，河马血吸虫不能被认为与曼氏血吸虫同义。假设河马是河马血吸虫的正常宿主，系统发育分析与血吸虫和有蹄类动物之间的古老关联是一致的。
