What is a prion and why might plants have them?

In biology, nearly everything resists easy classification. Take, for example, the prion. The name is unassuming, but their behavior is vicious: these misfolded proteins cause Mad Cow disease and sometimes pass to humans through our food supply. Once misfolded, prions recruit other, normal copies of themselves and cause more misfolding, which leads to nasty aggregations of prions in the brain. The effect of these masses on the brain is evidenced in the medical name of Mad Cow disease: bovine spongiform encephalopathy, which roughly translates to “spongy brain disease.”

Prions, however, are not always delinquents.

Mobile DNA prefers a more flexible option

DNA is frequently presented as simply a book of instructions for the creation of life. We see it as a sleek, gently twisting ladder comprised of parallel rungs, called bases. In the right sequence, these bases make up the genes that color our hair and shape our features. That’s all DNA is, right?