title: Molecular delineation of Cylicocyclus nassatus and C. ashworthi (Nematoda:Strongylidae).
abstract: The nucleotide sequences of the first internal transcribed spacer (ITS-1), 5.8S gene and second internal transcribed spacer (ITS-2) of ribosomal DNA have been determined for Cylicocyclus nassatus, C. ashworthi and C. insignis. Pairwise comparisons revealed sequence differences between the taxa ranging from 3.8 to 6.2% for the ITS-2 and 2.2-2.7% for the ITS-1. For the ITS-1, the level of the sequence difference between C. ashworthi and C. nassatus (2.2%) was equivalent to that between C. nassatus and C. insignis (2.2%), indicating that C. ashworthi and C. nassatus represent separate species. Theoretical restriction maps were constructed from the sequence data, and a polymerase chain reaction-linked restriction fragment length polymorphism (PCR-linked RFLP) technique was established to unequivocally distinguish C. ashworthi from C. nassatus.
authors.affiliation: Department of Veterinary Science, University of Melbourne, Werribee, Victoria, Australia. hung@vet-science.unimelb.edu.au
authors.forename: G C
authors.initials: GC
authors.lastname: Hung
authors.forename: N B
authors.initials: NB
authors.lastname: Chilton
authors.forename: I
authors.initials: I
authors.lastname: Beveridge
authors.forename: A
authors.initials: A
authors.lastname: McDonnell
authors.forename: J R
authors.initials: JR
authors.lastname: Lichtenfels
authors.forename: R B
authors.initials: RB
authors.lastname: Gasser
mesh_terms: D000818:Animals; D001483:Base Sequence; D018509:DNA, Helminth / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D017238:Genes, Helminth; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015183:Restriction Mapping; D016415:Sequence Alignment; D013045:Species Specificity; D013320:Strongyloidea / Q000145:classification* / Q000235:genetics*
chemical_list: D018509:DNA, Helminth; D004275:DNA, Ribosomal