Allelic variants of ovine prion protein gene (PRNP) in Oklahoma sheep

1,144 sheep belonging to 21 breeds and known crosses were sequence analyzed for polymorphisms in the ovine PRNP gene. Genotype and allele frequencies of polymorphisms in PRNP known to confer resistance to scrapie, a fatal neurodegenerative disease of sheep, are reported. Known polymorphisms at codons 136 (A/V), 154 (H/R) and 171 (Q/R/H/K) were identified. The frequency of the 171R allele known to confer resistance to type C scrapie was 53.8% and the frequency of the 136A allele known to influence the resistance to type A scrapie was 96.01%. In addition, we report the identification of five new polymorphisms at codons 143 (H/R), 167 (R/S), 180 (H/Y), 195 (T/S) and 196 (T/S). We also report the identification of a novel allele (S/R) at codon 138.