dubois@uwmacc.UUCP (Paul DuBois) (04/16/85)
>> [Paul DuBois] >> You had better go look up what the central dogma is. It's NOT my >> term. I didn't make it up. > [Michael Ward] > I would love to look this up, if I know what you meant. Please > clarify what it is you are asking me to look up. The meaning > of the terms, the dogma itself? If so the dogma of what? Apologies for being so curt. The Central Dogma is, in brief: everything's genetic. The proposition is that DNA is the sole repository of biological information and that the flow of such information is one-way, from the DNA to elsewhere (usually protein). (This is probably an oversimplification; maybe Mike Huybensz or Stanley Friesen will comment.) Opinion is somewhat divided about the status of the Dogma: Peter Calow (_Evolutionary Principles_. Blackie, Glasgow, 1983) says "the Central Dogma remains inviolate" [p24]. This is in rather striking contrast to Pierre Grasse' (_Evolution of Living Organisms: Evidence for a New Theory of Transformation_. Academic Press, New York, 1977, pp220-222) treats it with contempt. He says that the edifice of the concept was shattered from top to bottom almost as soon as it was formulated. (This reaction should not be a surprise: the Central Dogma comes from the Synthesis; Grasse' is, like many (most?) French biologists, a non-Darwinist.) Yockey maintains that the Dogma is a mathematical property of the genetic code. This is based on the observation that the mapping of information from codon to amino acid *must* be one-way, since the code is degenerate. I think it might be said that Yockey's treatment is intended for a rather more limited domain than that to which I alluded. (Hubert P Yockey, "Can the Central Dogma be Derived from Information Theory?". J Theoretical Biology, 74, 1978, 149-152.) My comment was directed to the idea that cultural transmission of information may provide a non-genetic way of propagating change, and in that way circumvents the Dogma. I suppose the question then becomes, is all behavior genetic? If it is, then of course the Dogma remains intact. -- | Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois --+-- | Science is Dead. |
mrh@cybvax0.UUCP (Mike Huybensz) (04/17/85)
In article <901@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes: > The Central Dogma is, in brief: everything's genetic. The proposition > is that DNA is the sole repository of biological information and that > the flow of such information is one-way, from the DNA to elsewhere > (usually protein). (This is probably an oversimplification; maybe > Mike Huybensz or Stanley Friesen will comment.) That's pretty much it. DNA -> RNA -> protein. There are some clear exceptions to this pathway. For example, it was dicovered that certain viruses produce an RNA reverse transcriptase that does this: RNA -> DNA. Prions (such as Kuru) are thought to go: protein -> ? -> protein. There are probably more examples that I don't remember offhand. Is it really a dogma? The DNA -> RNA -> protein pathway was found, and the hypothesis was made that because it was sufficient to explain what we knew about life then, that was all. It has since been found that there are additional pathways. This sort of procedure is a normal aspect of science: make a hypothesis to provide direction to research, looking for confirmations and exceptions to the hypothesis. As more is learned, the original hypothesis often represents what is known more and more poorly. Just as Newton's laws of motion are special cases under the theory of relativity, so the "Central Dogma" is a special case (albeit the most important one) under what we know today. > My comment was directed to the idea that cultural transmission of > information may provide a non-genetic way of propagating change, and > in that way circumvents the Dogma. I suppose the question then > becomes, is all behavior genetic? If it is, then of course the Dogma > remains intact. Transmission of parasites is also a non-genetic way of propagating change. But that's besides the point. There are non-genetic ways of propagating change. Formulating the "Central Dogma" theory was a method of requiring explicit testing and identification of modes of propation of biological information. For a while, it was thought that learning or memory might be encoded in DNA, RNA, or proteins. It now seems to be encoded in synapses and proteinaceous pathways within neurons. The Central Dogma helped point out the mechanisms that would be required for the former: when they were looked for and not found, research shifted. -- Mike Huybensz ...decvax!genrad!mit-eddie!cybvax0!mrh