Devoid of DNA, Infectious Prions Evolve Anyhow
It has long been thought that prions can't evolve. Turns out they can Scientists from the Scripps Research Institute have discovered that prions -- tiny infectious bits of protein that can cause deadly neurodegenerative disease -- are capable of evolution. While that might not seem groundbreaking, here's the thing: while prions evolve by Darwinian, naturally selective processes, they are completely devoid of DNA and RNA. Mammals produce the normal protein cousins of infectious prions as part of normal cell development, but during infection, misfolded or warped proteins can convert normal host prion protein into its own toxic, misfolded form. When this happens enough times, massive tissue and cell damage can occur. Infectious prions are linked to a number of fatal and untreatable diseases in humans and other animals, including mad cow disease and its rare human equivalent. While prions have no nucleic acid genome component -- DNA or RNA -- they...