Molecular characterization of Fasciola hepatica, Fasciola gigantica, and aspermic Fasciola sp. in China based on nuclear and mitochondrial DNA

Abstract

Parthenogenic Fasciola forms as well as bisexual Fasciola hepatica and Fasciola gigantica in mainland China have been identified on the basis of their spermatogenesis and genotypes in nuclear ribosomal internal transcribed spacer 1 (ITS1) and mitochondrial NADH dehydrogenase I (NDI). The Chinese aspermic Fasciola would include forms originating in interspecific hybrids between F. hepatica and F. gigantica, since they showed the genotype of ITS1-Fh/Fg that had mixed sequences of the two Fasciola species or heterogeneous genotypes in ITS1 and NDI. Additionally, there were Chinese aspermic flukes in which the sequences of ITS1 and NDI genotypes completely coincided with those in aspermic forms from Japan, Korea, and Vietnam, suggesting that the aspermic forms from these four countries are offspring with a common provenance. The Fh-C4 haplotype in NDI was detected in both aspermic specimens and F. hepatica, indicating that aspermic forms showing the haplotype might come into existence in China. The ratio of body length and width in aspermic Fasciola specimens showed intermediate values between those of F. hepatica and F. gigantica.

Morphometric and Molecular Study of Fasciola Isolates from Ruminants in Iran

“…Additionally, the hybridization phenomenon occurs where both species co-exist. Fasciola forms intermediate between F. hepatica and F. gigantica have been reported from Asian countries, including Korea (11), Japan (12), Iran (13), China (14), and Vietnam (15,16) as well as African countries including Egypt (17,18).…”

DNA Types of Aspermic Fasciola Species in Japan

“…Although Fasciola specimens in Japan have been considered to be of the same origin as that of aspermic Fasciola specimens in Korea, China and Vietnam [7][8][9]16], the frequency of DNA type combinations in Japanese specimens apparently differs from that in those three countries (e.g., the combination of Fsp1/2 in ITS1 and Fsp2 in ND1 is conspic- Table 1. ), M: 100 bp DNA ladder.…”

A description of karyotype of the giant liver fluke Fascioloides magna (Trematoda, Platyhelminthes) and a review of Fasciolidae cytogenetics

“…The karyotype of F. magna, described here in detail for the first time, differs from chromosome sets of all other fasciolids by higher diploid number 2n = 22. Namely, F. hepatica and F. gigantica have 2n = 20; triploid forms, reported often in both species and in Fasciola sp., have 3n = 30 (Sanderson, 1953;Terasaki et al, 2000;Itagaki et al, 2009 and references therein). The chromosome number 2n = 20 is characteristic also for P. fascioaemorpha (Baršiené, 1990).…”

“…exhibit not only diploid, but also triploid populations and even mixoploid (2n/3n) specimens (e.g. Moriyama et al, 1979;Sakaguchi, 1980;Terasaki et al, 1998Terasaki et al, , 2000Itagaki et al, 2009;Srimuzipo et al, 2000;Ichikawa & Itagaki, 2010). Additionally, triploid F. hepatica has been found in Britain and Ireland (Fletcher et al, 2004).…”

“…Additionally, triploid F. hepatica has been found in Britain and Ireland (Fletcher et al, 2004). Recent molecular studies have suggested that the origin of Asian triploids may be hybridization between F. hepatica and F. gigantica (Itagaki & Tsutsumi, 1998;Agatsuma et al, 2000;Lin et al, 2007;Itagaki et al, 2009;Peng et al, 2009). Moreover, Terasaki et al (2000), Fletcher et al (2004) and Dreyfuss & Rondelaud (2008) suggest that triploidy in Fasciola spp.…”