title: Differences in the second internal transcribed spacer (ITS-2) of eight species of gastrointestinal nematodes of ruminants.
abstract: Genetic differences in the nucleotide sequence of the second internal transcribed spacers (ITS-2) among Trichostrongylus axei, Trichostrongylus colubriformis, Ostertagia ostertagi, Cooperia oncophora, Cooperia punctata, Nematodirus helvetianus, Nematodirus filicollis, and Haemonchus contortus are described. The ITS-2 sequences of the 8 species ranged between 230 and 241 base pairs in length. Sequence similarities between the different genera varied between 60% and 80%. Identities between the different species within a genus varied between 99% for C. oncophora and C. punctata, 95% for T. axei and T. colubriformis, and 89% for N. helvetianus and N. filicollis. The ITS-2 sequences proved to be useful for species differentiation. Except for the species of Cooperia (2.07% intraspecific variations for C. oncophora and 0.83% for C. punctata) the degree of intraspecific variations (N. filicollis 0.85%, T. colubriformis 1.26%, T. axei 1.27%, H. contortus 2.60%, O. ostertagi, and N. helvetianus no variation) was markedly lower than the interspecific variations allowing a reliable differentiation within the ITS-2 region between single species.
authors.affiliation: Institute of Parasitology, Hannover School of Veterinary Medicine, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Heise
authors.forename: C
authors.initials: C
authors.lastname: Epe
authors.forename: T
authors.initials: T
authors.lastname: Schnieder
mesh_terms: D000818:Animals; D001483:Base Sequence; D018509:DNA, Helminth / Q000737:chemistry*; D004275:DNA, Ribosomal / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel / Q000662:veterinary; D014644:Genetic Variation; D007411:Intestinal Diseases, Parasitic / Q000469:parasitology / Q000662:veterinary; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012418:Ruminants / Q000469:parasitology*; D016415:Sequence Alignment / Q000662:veterinary; D013045:Species Specificity; D014251:Trichostrongyloidea / Q000145:classification / Q000235:genetics*; D014252:Trichostrongyloidiasis / Q000469:parasitology / Q000662:veterinary
chemical_list: D018509:DNA, Helminth; D004275:DNA, Ribosomal