Mad cows meet mad yeast: The prion hypothesis

Obscure work on the inheritance of two peculiar genetic traits in yeast has recently collided with work on infectious, neurodegenerative diseases in mammals. The impact illuminates both fields. The yeast work reveals a new mechanism of genetic variation that is based on differences in protein conformation rather than differences in nucleic acid. In the light of this work the prion hypothesis for transmissible neurodegenerative disease no longer seems so bizarre. Indeed, the mammalian prion hypothesis is now placed within a larger framework that is likely to be of universal importance in biology. Yeast prions, as the genetic elements are called, can be cured, offering new insights into the molecular processes involved in protein-based inheritance and new hope for the treatment of neurodegenerative diseases in man.