title: Genetic characterization of the blood-sucking nematodes Libyostrongylus dentatus and Libyostrongylus douglassii supports their different evolutionary history.
abstract: Libyostrongylus sp. are nematodes that infect ostriches. Libyostrongylus douglassii was first described in ostriches from several countries in the world. Later Libyostrongylus dentatus was morphologically identified in ostriches in the USA and Brazil, and mixed infection is common in the latter country. The internal transcribed spacer (ITS) region of the ribosomal DNA gene is used for genetic variability assessment and phylogenetic reconstruction for many organisms. Through genetic analysis the status of different species morphologically defined was confirmed and a molecular method was developed to differentiate both species. ITS1, 5.8S, ITS2 regions of L. douglassii and L. dentatus were characterized. Regarding complete ITS region, the K2-p genetic distance between the species was 0.060 (SE 0.008) and the intra-specific distance was 0.002 (SE 0.001) for L. dentatus and 0.006 (SE 0.002) for L. douglassii. NJ and MP phylogenetic analysis of ITS1 and ITS2 regions indicated that both species belong to the Trichostrongylidae family, and are evolutionarily different, suported by high bootstrap value. Based on ITS DNA polymorphisms, a molecular approach was designed to detect both species. These results are the first molecular characterization of L. douglassii and L. dentatus, and provide new tools for the identification of these parasites of veterinary importance.
authors.affiliation: Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, 28013-602 Campos dos Goytacazes, RJ, Brazil.
authors.forename: Josiana G
authors.initials: JG
authors.lastname: Andrade
authors.forename: Alena M
authors.initials: AM
authors.lastname: Iñiguez
authors.forename: Adriane N
authors.initials: AN
authors.lastname: Souza
authors.forename: Valéria C L
authors.initials: VC
authors.lastname: Marques
authors.forename: Gonçalo A
authors.initials: GA
authors.lastname: de Souza Filho
authors.forename: Clóvis P
authors.initials: CP
authors.lastname: Santos
authors.forename: Renato A
authors.initials: RA
authors.lastname: DaMatta
mesh_terms: D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D001715:Bird Diseases / Q000469:parasitology; D018509:DNA, Helminth / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D008969:Molecular Sequence Data; D009348:Nematoda / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D020310:Struthioniformes
chemical_list: D018509:DNA, Helminth; D021903:DNA, Ribosomal Spacer