EN
The objective of this research was to determine allele and genotype frequencies of the prion protein gene (PRNP) in a flock of sheep and categorise thereof into groups by susceptibility to scrapie. Additionally, a mating simulation was conducted, which aimed at decreasing sheep susceptibility to scrapie. Sheep of Kamieniecka breed from a single flock were investigated. Polymorphism in the PrP gene was identified with the use of the PCR-RFLP method. Four of the five alleles were found - ARR, ARQ, ARU. and VRQ, in nine different combinations - ARR/ARR, ARR/ARQ, ARQ/ARQ, ARR/ARH, ARH/VRQ, ARR/VRQ, ARQ/ARH, ARH/ARH, and ARQ/VRQ. The most frequent allele was the one being the most desired, namely ARR, (63.2%), and the least frequent was VRQ (5.4%). Mating simulation aiming at increasing the frequency of the ARR allele in the examined sheep group demonstrated that in the F₆ generation it is possible to obtain as many as 97.7% of homozygotic animals having the lowest susceptibility to scrapie.