Prions Evolve, Scripps Florida Study Finds

Prions, those mysterious bits of protein that can cause Creutzfeldt-Jakob disease , kuru , mad cow disease and scrapie, evolve according to Darwin's theory of evolution by natural selection. Researchers at The Scripps Research Institute's branch in Jupiter, Florida, announced the findings in the Dec. 31 online issue of the journal Science.

Prions are proteins that we all have. Prion diseases are caused by mistakes in folding these proteins. While DNA codes for making proteins, they form extremely intricate 3D structures that help determine their function. A misfolded protein, caused by some post-transcription error, can catalyze formation of other proteins, and the end result is prion disease. In other words, prion disease are not genetic diseases, although genes play a role in vulnerability.

Prions can evolve drug resistance and other beneficial mutations (from the prion's point of view, at least), like living things do, the study found. Prion diseases are remorseless and, as far as we know, 100 percent fatal, as the victims' brains are chewed away by the deadly protein.

It shouldn't be surprising that Darwinian evolution be found in prions, which after all are organic molecules. Darwin's insights have penetrated far afield from his original observation of evolution in whole organisms. Darwinian evolution has been used to design chemicals from mutation and directed selection of molecules, computerized and even used to create software programs .

From the press release:


"In the first part of the study, Weissmann and his colleagues transferred prion populations from infected brain cells to culture cells. When transplanted, cell-adapted prions developed and out-competed their brain-adapted counterparts, confirming prions' ability to adapt to new surroundings, a hallmark of Darwinian evolution. When returned to brain, brain-adapted prions again took over the population.




