title: Characterization of the intergenic spacer rDNAs of two pig nodule worms, Oesophagostomum dentatum and O. quadrispinulatum.
abstract: The characteristics of the intergenic spacer rDNAs (IGS rDNAs) of Oesophagostomum dentatum and O. quadrispinulatum isolated from pigs in different geographical locations in Mainland China were determined, and the phylogenetic relationships of the two species were reconstructed using the IGS rDNA sequences. The organization of the IGS rDNA sequences was similar to their organization in other eukaryotes. The 28S-18S IGS rDNA sequences of both O. dentatum and O. quadrispinulatum were found to have variable lengths, that is, 759-762 bp and 937-1128 bp, respectively. All of the sequences contained direct repeats and inverted repeats. The length polymorphisms were related to the different numbers and organization of repetitive elements. Different types and numbers of repeats were found between the two pig nodule species, and two IGS structures were found within O. quadrispinulatum. Phylogenetic analysis showed that all O. dentatum isolates were clustered into one clade, but O. quadrispinulatum isolates from different origins were grouped into two distinct clusters. These results suggested independent species and the existence of genotypes or subspecies within pig nodule worms. Different types and numbers of repeats and IGS rDNA structures could serve as potential markers for differentiating these two species of pig nodule worms.
authors.affiliation: Laboratory of Parasitology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, China.
authors.forename: Rui-Qing
authors.initials: RQ
authors.lastname: Lin
authors.affiliation: Laboratory of Parasitology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, China ; Yong Nian Veterinary Station, Fushun, Sichuan 643200, China.
authors.forename: Li
authors.initials: L
authors.lastname: Shu
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Zhao
authors.affiliation: Laboratory of Parasitology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Cheng
authors.affiliation: Laboratory of Parasitology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, China.
authors.forename: Shang-Shu
authors.initials: SS
authors.lastname: Zou
authors.affiliation: Laboratory of Parasitology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Laboratory of Parasitology, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, China.
authors.forename: Ya-Biao
authors.initials: YB
authors.lastname: Weng
mesh_terms: D000818:Animals; D001483:Base Sequence; D002681:China; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D023061:Gene Order; D005843:Geography; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009815:Oesophagostomum / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013552:Swine / Q000469:parasitology*
chemical_list: D017931:DNA Primers; D021903:DNA, Ribosomal Spacer