PRNP and scrapie: About 15 years ago, the European Union (EU), as well as other countries, started to select for sheep carrying the PRNP haplotype A136R154R171 (ARR), which was regarded to be resistant to classical scrapie, and to eliminate the other haplotypes, especially VRQ, which was suspected to be most susceptible (Dawson et al. 1998; Dubois et al. 2002; Baylis et al. 2004; Vitezica et al. 2005).