GENETIC-MARKERS FOR STRONGYLID NEMATODES OF LIVESTOCK DEFINED BY PCR-BASED RESTRICTION ANALYSIS OF SPACER RDNA

Twenty-four species of parasitic nematode (order Strongylida) from she ep, goats, cattle or pigs were characterised using a polymerase chain reaction-linked restriction fragment length polymorphism technique (PC R-RFLP). The ribosomal (r)DNA region spanning the first internal trans cribed spacer (ITS-1), 5.8S rRNA gene and the second internal transcri bed spacer (ITS-2) (designated ITS) was amplified from genomic DNA by polymerase chain reaction (PCR), digested separately with four restric tion endonucleases (RsaI, HinfI, DraI or NlaIII) and the fragments sep arated by agarose gel electrophoresis. The PCR products amplified from all species appeared as a single band of similar to 870 bp in size, e xcept for Ostertagia ostertagi whose product was similar to 1250 bp. T he PCR-RFLP analysis of ITS revealed characteristic restriction patter ns for all species, except for C. surnabada and C, oncophora which had identical patterns. The study demonstrated that ITS contains useful g enetic markers for the identification of a range of strongylid nematod es of livestock. These markers should be: of use in specific PCR assay s for the identification of developmental stages of the parasites wher e morphological characters are unreliable. (C) 1998 Elsevier Science B .V. All rights reserved.