Prion protein gene polymorphisms in pedigree sheep in Ireland

The development of clinical signs of scrapie in sheep has been linked to polymorphisms in the prion protein (PrP) gene. The most important polymorphisms appear to be at codons 136, 153 and 171. The objective of this study was to investigate polymorphisms at these codons in five native (Belclare, Galway, Wicklow Cheviot, Donegal Blackface Mountain and Mayo Blackface Mountain) and five imported (Texel, Bleu du Maine. Rouge de l'Ouest, Vendeen and Charollais) sheep breeds in Ireland. A total of 13 genotypes were found. The percentage of the most resistant genotype AA(136)RR(154)RR(171) varied from 1.8 per cent in the Vendeen breed, 3.1 per cent in Donegal Blackface Mountain, 10.0 per cent in Texel. 11.1 per cent in Wicklow Cheviot, 12.9 per cent in Belclare, 22.0 per cent in Charollais, 25.6 per cent in Mayo Blackface Mountain, 33.3 per cent in Galway, 46.4 per cent in Bleu du Maine to 62.5 per cent in Rouge de l'Ouest. The results indicate that a significant amount of variation exists between the breeds analysed in this study. (C) 2001 Harcourt Publishers Ltd.