Changes in allele and genotype frequencies of PrP gene in breeds of sheep in Slovakia between 2004 and 2015

The objective of the study was to analyze the changes in allele and genotype frequencies of PrP gene in auction purebred rams of various breeds in Slovakia between 2004 and 2015. Male genotyping was done within the National Scrapie Eradication Programme by the certified laboratories. Positive changes in all breeds were found during the analyzed period. As a result of strict positive selection for ARR allele and strict negative selection for VRQ and ARQ alleles in most numerous Improved Valachian (IV) and Tsigai (TS) breeds, 94.7 % (IV) and 95.7 % (TS) of animals were included in the first and second risk (R1 and R2) groups in 2015. Frequencies of ARR allele were above 0.9 in specialized meat breeds. In Lacaune breed, frequencies of ARR, ARQ and VRQ alleles were 0.896, 0.117 and 0.003 in 2015. All purebred East Friesian males were included in R1 and R2 groups in 2015.