The transmission results for atypical scrapie were also analysed in relation to the prnp genotype of the sheep that were the source of the infectious agent, by comparing group 1a (animals with increased susceptibility to atypical scrapie and with the AF141RQ or AHQ prnp alleles) and group 1b (animals without AF141RQ or AHQ prnp alleles) [14], [15]. The gene discussed is PRNP; the disease is scrapie.