The data in Figure 4 also show that in contrast, Tg(CerPrP-E226)5037+/− mice inoculated with head homogenate from 40 day old cervid PrP Drosophila exposed at the larval stage to prion-free cervid brain homogenate, or 40 day old 51D Drosophila exposed at the larval stage to experimental CWD inoculum failed to develop murine prion disease (Figure 4b, d, e). The gene discussed is PRNP; the disease is prion disease.