title: Assessing sequence variation in the internal transcribed spacers of ribosomal DNA within and among members of the Contracaecum osculatum complex (Nematoda: Ascaridoidea: Anisakidae).
abstract: The anisakid nematodes of seals from different geographical origins, previously identified as Contracaecum osculatum A, C. osculatum B, C. osculatum C, C. osculatum D, C. osculatulm E and C. osculatum baicalensis by multilocus enzyme electrophoresis, were characterised using a DNA approach. The first and second internal transcribed spacers (ITS-1, ITS-2) of ribosomal DNA (rDNA) were individually amplified by polymerase chain reaction (PCR) and analysed by single-strand conformation polymorphism (SSCP) and sequencing. SSCP analyses allowed the unequivocal differentiation of all taxa except C. osculatum D from C. osculatum E. While C. osculatum D and C. osculatum E had identical ITS sequences, each of the other four taxa had distinct sequences, with interspecific differences ranging from 0.3% to 2.3%. C. osculatum C was genetically the most distinct taxon with respect to all other members of the species complex.
authors.affiliation: Department of Veterinary Science, The University of Melbourne, Werribee, Victoria, Australia.
authors.forename: X
authors.initials: X
authors.lastname: Zhu
authors.forename: S
authors.initials: S
authors.lastname: D'Amelio
authors.forename: L
authors.initials: L
authors.lastname: Paggi
authors.forename: R B
authors.initials: RB
authors.lastname: Gasser
mesh_terms: D000818:Animals; D001199:Ascaridoidea / Q000145:classification* / Q000235:genetics; D001483:Base Sequence; D021901:DNA, Intergenic / Q000235:genetics*; D014644:Genetic Variation; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D015183:Restriction Mapping; D046048:Seals, Earless / Q000469:parasitology*; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
chemical_list: D021901:DNA, Intergenic