Genetic susceptibility to scrapie in a population of Latxa breed sheep in the Basque Country, Spain

Abstract Resistance to natural scrapie in sheep has been associated with polymorphisms at codons 136, 154 and 171 of the prion protein (PrP). This study was undertaken to obtain preliminary information on the PrP gene-associated susceptibility to scrapie in the native sheep breed of the Spanish Basque Country (Latxa), where a single case of scrapie has been reported. Six hundred and ninetyeight sheep from 10 commercial scrapie-free flocks were analysed. The genotype associated with a higher resistance (ARR/ARR) was present in 5.9%, whereas that associated with the highest susceptibility (homozygous VRQ) was absent. ARQ/ARQ was the genotype most frequently observed (48.8%), indicating that susceptible animals exist in the absence of clinical disease. This study provides base-line data for genotype frequencies of Latxa breed that can be included among the criteria used for breed selection to increase the frequencies of resistant genotypes without losing out on other productive characteristics.