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Caprine prion gene polymorphisms are associated with decreased incidence of classical scrapie in goat herds in the United Kingdom

Wilfred Goldmann1*, Kelly Ryan1, Paula Stewart1, David Parnham1, Rosa Xicohtencatl2, Nora Fernandez2, Ginny Saunders3, Otto Windl3, Lorenzo González4, Alex Bossers5 and James Foster1

Author Affiliations

1 The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, UK

2 Facultad de Medicina Veterinaria y Zootecnia, Benemérita Universidad Autónoma de Puebla, Puebla, México

3 Animal Health and Veterinary Laboratories Agency, Weybridge, New Haw, Addlestone, Surrey, UK

4 Animal Health and Veterinary Laboratories Agency, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, UK

5 Central Veterinary Institute of Wageningen UR, Lelystad, The Netherlands

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Veterinary Research 2011, 42:110  doi:10.1186/1297-9716-42-110

Published: 31 October 2011

Abstract

The application of genetic breeding programmes to eradicate transmissible spongiform encephalopathies in goats is an important aim for reasons of animal welfare as well as human food safety and food security. Based on the positive impact of Prnp genetics on sheep scrapie in Europe in the past decade, we have established caprine Prnp gene variation in more than 1100 goats from the United Kingdom and studied the association of Prnp alleles with disease phenotypes in 150 scrapie-positive goats. This investigation confirms the association of the Met142 encoding Prnp allele with increased resistance to preclinical and clinical scrapie. It reveals a novel association of the Ser127 encoding allele with a reduced probability to develop clinical signs of scrapie in goats that are already positive for the accumulation of disease-specific prion protein in brain or periphery. A United Kingdom survey of Prnp genotypes in eight common breeds revealed eleven alleles in over thirty genotypes. The Met142 encoding allele had a high overall mean allele frequency of 22.6%, whereas the Ser127 encoding allele frequency was considerably lower with 6.4%. In contrast, a well known resistance associated allele encoding Lys222 was found to be rare (0.9%) in this survey. The analysis of Prnp genotypes in Mexican Criollas goats revealed nine alleles, including a novel Phe to Leu substitution in codon 201, confirming that high genetic variability of Prnp can be found in scrapie-free populations. Our study implies that it should be feasible to lower scrapie prevalence in goat herds in the United Kingdom by genetic selection.