No PrPres bands were observed in a Na-PTA extract of 90 mg tissue wet weight equivalent of a similarly prepared cotyledon homogenate derived from the shed placenta of scrapie-unexposed goat 4113 (Fig. 1a: cot, lane 3); this goat and cotyledon homogenate were also heterozygous for caprine PRNP haplotypes 1 and 2. Here, PRNP is linked to scrapie.