Distribution, origin and evolution of Fasciola japonicum in eastern Asia

在日本和韩国已经发现了单性生殖的片形吸虫。目前的研究表明，孤雌生殖片形吸虫也分布在越南和中国大陆，这表明整个亚洲国家的发生。基于核核糖体DNA（ITS1）和线粒体DNA（NDI基因）的分子生物学研究表明，肝片形吸虫（F.hepatica）和片形吸虫（F.arthritica）通过种间杂交和回交形成孤雌生殖型，并获得了孤雌生殖能力。新出生的孤雌生殖片形吸虫形式随着最终宿主如家牛传播到邻近的国家，如东部的韩国和日本以及南部的越南。

Parthenogenic Fasciola species have been known in Japan and Korea. The present study showed that parthenogenic Fasciola sp. also distributed in Vietnam and mainland China, suggesting occurrence throughout Asian countries. Molecular and phylogenical studies based on nuclear ribosomal DNA (ITS1) and mitochondrial DNA (NDI gene) suggested that parthenogenic Fasciola forms came into existence by resulting from interspecific hybridyzation between F.hepatica and F.gigantica and following backcross with the two species, and that they acquired the ability of parthenogenesis. New born parthenogenic Fasciola forms spread out with final hosts such as domestic cattle into neighboring counties as Korea and Japan in the east and Vietnam in the south.