USE OF RANDOM AMPLIFIED POLYMORPHIC DNA-POLYMERASE CHAIN-REACTION FORTHE DEFINITION OF GENETIC-MARKERS FOR SPECIES AND STRAINS OF PORCINE OESOPHAGOSTOMUM

Nodular worms are common parasites of pigs, and research has recently started to focus on the biology of these nematodes, However, the metho ds for delineation of species at immature developmental stages and for differentiation of various lines of the same species remain limited, For differentiation of porcine Oesophagostomum species and strains by genomic finperprinting, random amplified polymorphic DNA-polymerase ch ain reaction was performed on DNA derived from 20 larval batches of an thelmintic-susceptible and resistant strains and isolates of these nem atodes and 2 ruminant Oesophagostomum spp, Polymorphic DNA markers cou ld be amplified with 9 of the 33 primers tested, In all, 13 markers we re species-specific and 6 markers could differentiate between strains or groups of strains, With a combination of the latter, artificially s elected anthelmintic-resistant strains and the susceptible mother stra in of O. dentatum could be delineated. When single adult worms were co mpared, considerable variations between strains of the same species an d between individuals from the same strain could be detected, The diff erentiation of Oesophagostomum strains and species at all parasitic st ages on the basis of genetic markers could greatly facilitate studies on the biology of these parasites.