Restriction fragment length patterns of dna from parasitic nematodes of sheep

High molecular weight DNA obtained from sheep parasitic nematodes Haemonchus contortus, Ostertagia circumcincta and Trichostrongylus colubriformis, was digested with various restriction endonucleases. Digestion with Eco R1 produced the most informative pattern of repeat sequence bands. H contortus adult or larval dna produced bands of 2·7, 3·0 and 1·4 kb. O circumcincta adult or larval dna had common 2·7 and 1·4 kb bands with adult specific bands of 2·2 and 0·9 kb and a larval specific 2·08 kb band. T colubriformis adults or larval dna produced 2·7, 1·4 and 0·79 kb bands. These preliminary results show that restriction patterns of repeal sequence dna may be useful for the identification of various trichostrongylid species parasitic for sheep.