In order to evolve there has to be some kind of genetic information passed on to descendants. But for prions there is no such mechanism. A lower energy state is assumed and that's that.
And prions don't have descent with modification. It's a regular mammal brain protein that got accidentally constructed backwards. There's nothing to pass on, nothing to modify.
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?
> Prion replication is subject to epimutation and natural selection just as for other forms of replication, and their structure varies slightly between species.[19]
This got me wondering: what is the advantage of genetic information (DNA / RNA) over a self-replicating entity without those convenient molecules?
My impression is that DNA / RNA-based organisms have a high tolerance for changes to their DNA / RNA, such that many genetic changes won't cause them to lose their self-replicating ability. This is great for evolution.
Prions, on the other hand, seem like they would have a low reproductive tolerance for changes to their structure.
All evolutionary change (and life itself) is due a combination of differences of entropy (aka an energy gradient existing), combined with randomness in the current environment allowing mutation/change and hence selection pressure.
Evolution only requires "descent with modification". DNA is a mechanism for this, but it is not necessarily the only one.