Figure 1. Schematic diagram of structural features of mammalian prion proteins (top).

Sequence numbering is per the murine protein. Also depicted is an alignment of the sequences of important mammalian prion proteins in the β2–α2 loop region—sequence numbering on this part of the figure is precise and is taken from the protein sequences of each individual species. Boxes with solid lines represent the key amino acid differences between deer/elk and other species whilst the dashed box represents the polymorphic position in sheep that segregates with susceptibility to prion disease infection.