USE OF RANDOM AMPLIFIED POLYMORPHIC DNA FOR IDENTIFICATION OF RUMINANT TRICHOSTRONGYLID NEMATODES

The aim of this work was to evaluate random amplified polymorphic DNA (RAPD) as a source of markers for species identification and phylogene tic analysis of ruminant trichostrongylid nematodes. As these nematode s are often polymorphic, species identification may be difficult. We t ested eight species and several of their morphs: Haemonchus contortus (three vulvar morphotypes: flap, smooth, and knobbed), Teladorsagia ci rcumcincta, Ashworthius gagarini, Spiculopteragia boehmi, Ostertagia l eptospicularis (and its morph Ostertagia kolchida), Cooperia oncophora (and its morph C. surnabada), Trichostrongylus colubriformis, and T. vitrinus. With five chosen 10-mer primers, genetic variations were ass essed among individuals of each species or morphotype. In trichostrong ylid nematodes, the identification of species is possible by means of RAPD on adult or larva DNA extracts, although the variability observed within species was very important for most species stud led. The use of RAPD in phylogenetics studies is conversely questionable for this s uperfamily of parasitic nematodes. The interspecific distances were al ways larger than the intraspecific ones and did not vary much (between 0.8 and 0.9); they would not be of much use in the construction of a phylogenetic tree, at feast for the species and the primers involved i n this study.