The dogma of the Mendelians was in thinking of genetic coding as something exclusive that somehow transcended the physical world and interactions and processes in it.
http://www.newscientist.com/article/mg18324611.400 Lamarckism finds new lease of life in a prion * 21 August 2004 by Philip Cohen * Magazine issue 2461 EVOLUTION can occur in a way never previously shown. Geneticists have discovered that the strange proteins called prions can temporarily give yeast cells new powers which can then be quickly, and permanently, assimilated into their chromosomes. "This provides a novel way for organisms to try out different traits, survive and adapt to fluctuating environments," says Susan Lindquist who led the work at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts. The finding unexpectedly brings together the theories that Charles Darwin and his chief rival Jean-Baptiste Lamarck developed to explain evolution. http://cat.inist.fr/?aModele=afficheN&cpsidt=956708 Résumé / Abstract The experimental evidence accumulated for the last half of the century clearly suggests that inherited variation is not restricted to the changes in genomic sequences. The prion model, originally based on unusual transmission of certain neurodegenerative diseases in mammals, provides a molecular mechanism for the template-like reproduction of alternative protein conformations. Recent data extend this model to protein-based genetic elements in yeast and other fungi. Reproduction and transmission of yeast protein-based genetic elements is controlled by the prion replication machinery of the cell, composed of the protein helpers responsible for the processes of assembly and disassembly of protein structures and multiprotein complexes. Among these, the stress-related chaperones of Hsp100 and Hsp70 groups play an important role. Alterations of levels or activity of these proteins result in mutator or antimutator affects in regard to protein-based genetic elements. Protein mutagens have also been identified that affect formation and/or propagation of the alternative protein conformations. Prion-forming abilities appear to be conserved in evolution, despite the divergence of the corresponding amino acid sequences. Moreover, a wide variety of proteins of different origins appear to possess the ability to form amyloid-like aggregates, that in certain conditions might potentially result in prion-like switches. This suggests a possible mechanism for the inheritance of acquired traits, postulated in the Lamarckian theory of evolution. The prion model also puts in doubt the notion that cloned animals are genetically identical to their genome donors, and suggests that genome sequence would not provide a complete information about the genetic makeup of an organism. _______________________________________________ Marxism-Thaxis mailing list Marxism-Thaxis@lists.econ.utah.edu To change your options or unsubscribe go to: http://lists.econ.utah.edu/mailman/listinfo/marxism-thaxis
