Laboratory of Veterinary Parasitology, Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka 020-8550, Japan.
Parasitology. 2011 Sep;138(10):1278-84. doi: 10.1017/S0031182011000965. Epub 2011 Jul 18.
Experiments on hybridization between Fasciola hepatica and Fasciola gigantica were carried out to clarify whether a reproductive isolating mechanism appears between the two Fasciola species. Molecular evidence for hybridization was based on the DNA sequence of the internal transcribed spacer 1 (ITS1) region in nuclear ribosomal DNA, which differs between the species. The results suggested that there were not pre-mating but post-mating isolating mechanisms between the two species. However, viable adults of the hybrids F1 and F2 were produced from both parental F. hepatica and F. gigantica. The hybrids inherited phenotypic characteristics such as ratio of body length and width and infectivity to rats from parental Fasciola hepatica and F. gigantica. These findings suggest that reproductive isolation is incomplete between Fasciola hepatica and F. gigantica. Adults of the hybrids F1 and F2 were completely different in mode of reproduction from aspermic Fasciola forms that occur in Asia and seem to be offspring originated from hybridization between F. hepatica and F. gigantica and to reproduce parthenogenetically.
进行了肝片吸虫和巨型片形吸虫之间杂交的实验，以阐明这两种片形吸虫之间是否存在生殖隔离机制。杂交的分子证据基于核核糖体 DNA 中内部转录间隔区 1（ITS1）区域的 DNA 序列，该序列在物种间存在差异。结果表明，这两个物种之间存在交配后而不是交配前的隔离机制。然而，从亲本肝片吸虫和巨型片形吸虫中产生了可育的杂交 F1 和 F2 成虫。杂种继承了来自亲本肝片吸虫和巨型片形吸虫的表型特征，如体长与体宽比和对大鼠的感染力。这些发现表明肝片吸虫和巨型片形吸虫之间的生殖隔离不完全。杂交 F1 和 F2 成虫在繁殖方式上与亚洲出现的无精囊片形吸虫形式完全不同，它们似乎是肝片吸虫和巨型片形吸虫之间杂交的后代，并通过孤雌生殖繁殖。
