A prion is an (transmissible)
protein able to by transforming
other proteins a copy of the .
The mechanism of copying not yet
understood by .

The hypothesis come out research
about a nervous disease known
as Creutzfeldt-Jacob ,
epidemiologically associated to a
disease called bovine spongiform
(the mad cow disease).
discovered that the infectious
that causes those diseases,
, was a protein capable
copying itself and of transmitted
by ingestion (the why meat from
contaminated cannot be
consumed), inoculation even
heredity.