DNA-less Evolution

See allHide authors and affiliations

Science  12 Feb 2010:
Vol. 327, Issue 5967, pp. 759
DOI: 10.1126/science.327.5967.759-c

Prions are proteinaceous infectious elements involved in a variety of neurodegenerative diseases, including scrapie in sheep and so-called mad cow disease in cattle. Now Li et al. (p. 869, published online 31 December) show that, when propagated in tissue culture cells, cloned prion populations become diverse by mutational events and can undergo selective amplification. Thus, even though devoid of a coding genome, prions, when propagated under a particular selection regime, can be subject to rapid evolution.

Navigate This Article