Characterization ofDicrocoelium dendriticumisolates from small ruminants in Shaanxi Province, north-western China, using internal transcribed spacers of nuclear ribosomal DNA

Abstract

The genetic variations in internal transcribed spacers (ITS) spanning ITS-1, 5.8S and ITS-2 rDNA of Dicrocoelium dendriticum, isolated from sheep and goats in four geographical regions in Shaanxi province, were examined. The lengths of ITS-1, 5.8S and ITS-2 rDNA sequences for D. dendriticum were 749 bp, 161 bp and 234 bp, respectively. Intra-specific sequence variations of D. dendriticum were 0-0.5% for ITS-1 and 0-1.3% for ITS-2 rDNA, while the inter-specific variations among species in genus Dicrocoelium in ITS-2 rDNA were 3.4-12.3%. Phylogenetic analysis based on sequences of ITS-2 rDNA showed that all D. dendriticum isolates in the present study were grouped with reference D. dendriticum isolates from sheep and goats, and D. dendriticum isolates from cattle and Japanese serow were clustered in a sister clade. However, the phylogenetic tree could not reveal geographically genetic relationships of D. dendriticum isolates in different origins and hosts. These findings provided basic information for further study of molecular epidemiology and control of D. dendriticum infection in Shaanxi province as well as in the world.

Molecular analysis of selected paramphistome isolates from cattle in southern Africa

“…The results indicate that ITS2 is a reliable marker to study phylogenetic relationships between species, sub-families and genera, but not a good marker to infer phylogenetic relationships within species as in the case of C. microbothrium. This supports similar observations by Bian et al (2013).…”

Redescription and phylogenetic relationships of the rare Lyperosomum sarothrurae Baer, 1959 (Digenea: Dicrocoeliidae)

“…Some sequences of mitochondrial (mostly cox1) and nuclear DNA (mostly various fragments of the nuclear ribosomal DNA) from the representatives of the family have been published as part of studies dealing with either diagnostics of certain dicrocoeliid species, or broader systematic or ecological datasets (e. g., Tkach et al 2001, Zheng et al 2007, Kinsella and Tkach 2009, Sato et al 2010, Wang et al 2013, Bian et al 2015. Since publication of Tkach et al (2001) and Olson et al (2003), which outlined the position of the Dicrocoeliidae within the Digenea and indicated its closely related families, only a single study by Ribas et al (2012) presented a phylogenetic analysis focused on the dicrocoeliids.…”

Ribosomal DNA analysis of isolates of the liver fluke Opisthorchis pedicellata (Verma, 1927) from two siluroid fish species in India

“…Intraspecific variation of the ITS1 sequence (1.9%) exhibits 13 transitions and 17 transversions at 30 nucleotide positions. However, in D. dendriticum it differs by 0.5% (Bian et al ., 2013), 1.7% in C. sinensis (Xiao et al ., 2013), 1.0–5.2% in C. cichlasomae (Razo-Mendivil et al ., 2010) and 10.9% in M. eroliae (Al-Kandari et al ., 2011). The intraspecific variation in ITS2 sequences was found to be higher (2.6%) than those of the other molecular markers used in the present study, having seven transitions and six transversions at 13 nucleotide sites.…”

“…The intraspecific variation in ITS2 sequences was found to be higher (2.6%) than those of the other molecular markers used in the present study, having seven transitions and six transversions at 13 nucleotide sites. In Glypthelmins, it was reported to differ by 5.44% (Razo-Mendivil et al ., 2004) and by 1.3% in D. dendriticum (Bian et al ., 2013). A high degree of inter- and intraspecific genetic divergence at generic and species level is usually provided by the ITS2 region (McManus & Bowles, 1996; Itagaki et al ., 2003; Rinaldi et al ., 2005; Ghatani et al ., 2012), which was also observed in the present study.…”

“…Recent molecular biology techniques permit discrimination between closely related species by comparing ribosomal DNA (rDNA) sequences. Earlier workers have used nuclear ribosomal DNA sequences to confirm the identity of some digeneans, namely Dicrocoelium dendriticum (Bian et al ., 2013), Clonorchis sinensis (Xiao et al ., 2013), Glypthelmins (Razo-Mendivil et al ., 2004), Crassicutis cichlasomae (Razo-Mendivil et al ., 2010) and Maritrema eroliae (Al-Kandari et al ., 2011). The rDNA cluster is useful for platyhelminth systematics due to highly repeated and variable regions flanked by more conserved regions (Adlard et al ., 1993).…”