title: Genetic variation among Clonorchis sinensis isolates from different hosts and geographical locations revealed by sequence analysis of mitochondrial and ribosomal DNA regions.
abstract: The present study examined genetic variability among Clonorchis sinensis isolates from four different geographical localities (Guangzhou, Nanning, Jiamusi and Daqing) and host species (cats, dogs, human and rabbits) in Mainland China by sequence analyses of two mitochondrial DNA (mtDNA) genes, namely NADH dehydrogenase subunits 2, 5 (nad2 and nad5) and ribosomal internal transcribed spacer 1 (ITS1). A portion of the ITS1, nad2 (pnad2) and nad5 (pnad5) was amplified by polymerase chain reaction separately from adult C. sinensis individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of ITS1, pnad2 and pnad5 was 643, 666 and 771 bp, respectively. The intraspecific sequence variations within C. sinensis were 0-1.7% for ITS1, 0-1.4% for pnad2 and 0-0.9% for pnad5. The interspecific sequence variations within other zoonotic trematodes, which were published previously, were 4.5-84.9% for ITS1, 21.9-43.6% for pnad2 and 19.2-48.9% for pnad5. The A+T contents of the sequences were 45.26-45.88% (ITS1), 62.91-63.51% (pnad2) and 58.24-58.63% (pnad5). Phylogenetic analyses using ribosomal and mitochondrial sequence data set, with three different computational algorithms (Bayesian inference, maximum parsimony and maximum likelihood), all revealed distinct groups with high statistical support. These findings demonstrated the existence of low-level intraspecific variations in ribosomal DNA (rDNA) and mtDNA sequences among C. sinensis isolates from four different regions and hosts in China and elucidated that mtDNA sequences and rDNA sequences provided reliable genetic markers for phylogenetic studies of zoonotic trematodes.
authors: Department of Parasitology, College of Basic Medicine, Jiamusi University , Jiamusi, Heilongjiang Province , 154007 , People's Republic of China.
authors: Jing-Ying
authors: JY
authors: Xiao
authors: Jun-Feng
authors: JF
authors: Gao
authors: Lian-Shun
authors: LS
authors: Cai
authors: Yue
authors: Y
authors: Dai
authors: Chun-Jia
authors: CJ
authors: Yang
authors: Lan
authors: L
authors: Luo
authors: Takeshi
authors: T
authors: Agatsuma
authors: Chun-Ren
authors: CR
authors: Wang
mesh_terms: D000818:Animals; D002415:Cats; D003004:Clonorchis sinensis / Q000145:classification / Q000235:genetics*; D018509:DNA, Helminth / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D004285:Dogs; D014644:Genetic Variation; D005843:Geography; D006790:Host-Parasite Interactions / Q000235:genetics; D006801:Humans; D010802:Phylogeny; D011817:Rabbits; D017422:Sequence Analysis, DNA
chemical_list: D018509:DNA, Helminth; D004272:DNA, Mitochondrial; D004275:DNA, Ribosomal