02340nas a2200229   4500008004100000022004200041245004900083210004500132250001000177260000800187300001300195490000700208520173000215653001201945653001101957653000901968653003501977653002202012100001602034700001502050856004502065       1997                        eng d  a0305-1846 (Print) 0305-1846 (Linking)00aThe nature of transmission in prion diseases0 anature of transmission in prion diseases  a35643  cAug  a273 - 800 v233 aReplicating biological information is usually stored only within nucleic acid. The existence of 'strains' of agent in prion disease (scrapie, BSE, CJD) has been taken to indicate an independent genome within the transmissible agent. Other replicable information exists, however, both in biology and elsewhere, including, for example, the 'meme' (the neutral correlate of ideas which replicate in human brains by communication) and the computer virus. From this broader viewpoint, we explore the possibility that 'strain' differences in prion disease reflect biological information stored within the prion protein rather than in nucleic acid. Much of the disease variation in mice (used as evidence for strain differences) can be accounted for by the primary structures of the prion protein of the host (the experimentally infected mouse) and the donor mouse (from which infectious tissue is taken). Information determining residual disease variation (when these factors have been excluded) may reside in different conformational states of host prion protein. Prion protein can adopt different conformational and glycosylation states. The information which these states contain is only partially conserved on transmission between animals, permitting the appearances of both 'strain stability' and 'strain mutation'. Different sources of replicating, biological information including information in the 'agent' (the abnormal form of prion protein) and in the host prion gene (PRNP) are in evolutionary competition. We argue that, in the prion diseases, replicating information is not carried in nucleic acid in either the host or the 'agent' but is carried within the conformational state of the abnormal form of prion protein.10aAnimals10aHumans10aMice10aPrion Diseases / *transmission10aVirus Replication1 aRidley, R M1 aBaker, H F  uhttps://notifylibrary.org/reference/1317