Characterization of the prion protein gene (PRNP) region in Swiss sheep breeds

Polymorphisms in the PRNP gene have both an influence on the progress of scrapie and also of bovine spongiform encephalopathy (BSE) in sheep. In the light that sheep are potentially susceptible to BSE the goal of this project was to characterize 50 animals of each of the four major Swiss sheep breeds, namely Swiss Oxford Down, Swiss Black‐Brown Mountain, Valais Blacknose and Swiss White Alpine with respect to polymorphisms in the PRNP region. A 628‐bp fragment of exon 3 of PRNP comprising codons 112–211 was amplified by PCR and analysed by direct sequencing. Heterozygous genotypes were further verified by restriction fragment length polymorphism analyses. Polymorphisms could be observed at codons 112, 136, 137, 141, 143, 154 and 171 but not at codons 138, 151 and 211. One of the scrapie cases in Switzerland, a sheep of Swiss White Alpine, was also genotyped. Based on the polymorphisms observed at codons 136, 154 and 171 all four sheep breeds should be considered potentially susceptible to scrapie and BSE.