Err, I think I remember a couple pretty famous articles that contradicts that prions generally don't have descent with modification, which may be what the person above us is referring to:
That's really neat. Still there should be a limited number of possible variants right? Like the energy landscape is fixed and will only admit so many possibilities?
https://pubmed.ncbi.nlm.nih.gov/20044542/
https://pubmed.ncbi.nlm.nih.gov/17142317/