Russell Standish <[email protected]> wrote:
> >>>[The central dogma of molecular biology] deals with the detailed >>> states that such information cannot be transferred back from protein to >>> either protein or nucleic acid. >>> >>> >> >> I know of no example of a change in a protein making a systematic >> repeatable change (as opposed to a random mutation) in the sequence of >> bases in DNA that are passed onto the next generation. >> > > > Epigenetic information is expressed by the presence or absence of > methylation of the bases, not the sequence. > A keen grasp of the obvious. So because information is not being transferred from proteins to the base sequence of DNA I take it that you are retracting your statement that epigenesis contradicts the central dogma, not that it would matter because that is about molecular biology and we're talking about Darwin and Evolution. By the way, after the discovery of prions a couple of decades ago we knew that sometimes hereditary information can move from protein to protein and bypass DNA, so the central dogma is not 100% true, just 98 or 99% true. > > I'm not arguing that epigenetic, prebiotic or cultural evolution > Shouldn't be called "Darwinian". But in that case, Lamarkian evolution is > also "Darwinian", > And that’s exactly what I said in my first post on this thread, Lamarkian evolution can only work if its riding on the back of Darwin and his natural selection idea. > > Epigenetic changes show that there is more to hereditary information > than base pair sequence. > True without a doubt, so now the question is does that mean there is a lot more information or just a little bit more? My guess is it's just a little bit more, but as far as Darwin is concerned it doesn't matter. > >> Darwinian Evolution was what we are talking about! >> > > > Well, actually, what we started talking about was prebiotic evolution, > Darwin could explain how simple organisms could become more complex, but he didn't even attempt to explain how the first organism came into existence because before natural selection can kick in you need some sort of heredity. Recently there has been some discussion about clays playing a part in that because under some circumstances the atoms in the crystal lattice of clays can display a sort of very rudimentary heredity; it's a interesting thought but right now the idea is so sketchy it would be pushing it to call it a theory. > > the possibility of evolving an oprimised standard genetic code, to be > precise. > That idea has an interesting history. Soon after Francis Crick co-discovered the DNA double helix in 1953 he started to think about the genetic code. At the time only a few of the base triplets that map to amino acids were known, he thought he could find the remaining ones by theory alone, without experiment. When a ribosome reads a piece of RNA it can contain many millions of bases ATCCGATTC... and NO commas. Crick reasoned that just starting at the beginning and reading 3 at a time would be crazy. If you ever get out of phase by one or two you'd have no way to detect the phase error and the ribosome would make the wrong protein. It'd be like reading a book with no punctuation and nospacebetweenthewords, no engineer would stand for such a foolish design. Crick devised a code that if read in the correct phase all the triplets make sense, if read out of phase all the triplets would be nonsense, that is, they wouldn't map to any amino acid. Now the cell would know when it was reading RNA out of phase. He thought he understood why life only used 20 amino acids, his scheme would work with 20 amino acids it wouldn't work with 21. Cricks code was simple, efficient, elegant, fault tolerant and completely wrong. The real genetic code was found by experiment a few years later. Incredibly the ribosome really does just start at the beginning and plod along 3 at a time, if it gets out of phase and makes the wrong protein, well, that's just too bad. >> The central dogma of Evolution, both biological and cultural, has nothing to do with DNA or proteins or epigenesis. The central dogma of Evolution is: > >> 1) Heredity factors exist. >> 2) The process that transfers those factors is very reliable but is >> not perfect and so sometimes they change. >> 3) Because there are more ways to be wrong than to be right most (but >> not all) of those changes are harmful. >> 4) Some of those changed heredity factors will reproduce faster than >> others and become dominant in a population. >> >> > > Provide one citable source where the author uses the term "central > dogma" to describe the above > No. John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
