Studies on the speciation in the genus Paragonimus in south-east Asia

这些研究的目的是明确三倍体P. westermani的起源和亚洲P. westermani类群的物种形成机制，以及其医学意义。1987年7 - 9月，我们在中国和泰国对这一问题进行了联合实地调查。现就两年来双方在野外和实验室的联合研究成果作一简要报告。在中国大陆4个省11个地方采集的淡水蟹、闽南河蟹、长江南河蟹、闽南河蟹和小龙虾、达乌尔螯虾中分离到囊蚴并吸虫。从实验感染囊蚴的动物中获得成虫，鉴定为威氏绦虫。获得的吸虫有二倍体型和三倍体型。还发现了两种四倍体吸虫。来自中国东北的三倍体P. westermani （P. westermani）不仅在宿主特异性上，而且在电泳图谱上与日本的P. More一样。在中国大陆的二倍体P. westermani （P. westermani）中，电泳模式表现为多态性，而日本的二倍体则表现为单态，日本三倍体的特异等位基因在中国东北地区的二倍体群体中发现频率较高。因此，中国东北某二倍体类群在基因渐入性方面可能与日本三倍体的祖先有亲缘关系。在泰国，4种淡水蟹，Larnaudia larnaudii， L. beusekomae， Somanniathelphusa germaini和S. smithiana被证实自然感染了肺吸虫。根据实验获得的成虫形态特征，分别鉴定为异tremus、P. siamensis、P. bangkokensis和P. harinasutai。朱拉隆功大学（Chulalongkorn University）提供了机会，让人们可以观察附着的吸肺虫标本。虽然鉴定标本为二倍体，但尚未对泰国威氏马尼种群进行遗传研究。少

The objective of these studies is to make clear the origin of the triploid type of P. westermani and the mechanism of the speciation in the P. westermani group in Asia, together with its medical importance. We performed joint field investigations on this subject in China and Thailand during the period of July-September, 1987. The results of the joint reserch works in the field as well as those done in the laboratory over the last two years are briefly reported here.In mainland China, Paragonimus metacercariae were isolated from freshwater crabs, Sinopotamon fukienense, S. yangtsekiense, Malayopotamon fukienense and crayfish, cambaroides dauricus collected in 11 iocalities of 4 Provinces. The adults were obtained from the experimentally infected animals with the metacercariae, and were identified as P. westermani. The flukes obtained were diploid and triploid types. Two tetraploid flukes were also discovered. P. westermani (triploid type) from north-eastern China was almost same as the … More Japanese one not noly in host-specificity but also in electrophoretic patterns. In P. westermani (diploid type) from mainland China, the electrophoretic patterns showed polymorphism while those of the Japanese one were monomorphic, and the specific alleles of the Japanese triploids were found, in high frequency, especially in the diploid populations from north-eastern China. Therefore, a certain population (diploid type) of P. westermani group from northeastern China seems to be related to the ancestor of the Japanese P. westermani triploids in terms of the gene introgression.In Thailand, 4 species of the freshwater crabs, Larnaudia larnaudii, L. beusekomae, Somanniathelphusa germaini and S. smithiana were proved to be naturally infected with Paragonimus metacercariae. They were identified as P. heterotremus, P. siamensis, P. bangkokensis and P. harinasutai, based on their morphological features as well as those of the adults, obtained experimentally. Opportunity was offered at Chulalongkorn University to observe the mounted specimens of Paragonimus. Although the specimens were identified as P. westermani (diploid), the genetic studies on Thai P. westermani population have not been done yet. Less