On Mon, Aug 12, 2013 Russell Standish <li...@hpcoders.com.au> wrote:
> The central dogma of molecular biology deals with the detailed
> residue-by-residue transfer of sequential information.
Yes, but we're not talking about molecular biology, we're talking about
Evolution and it has a different central dogma.
> > It 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.
> Not all evolutionary processes have the central dogma
So what? As I said before, Darwin knew nothing about DNA or proteins or
epigenetic changes and he didn't need to; he knew nothing about the details
he only knew that there were hereditary factors of some sort that were
passed from one generation to the next, and because no process is perfect
he knew that there would sometimes be changes in that information, and he
knew that some of those factors would reproduce faster than others, and he
knew that the thing that would determine the winning factors from the
losing factors is natural selection.
> > What it means is that lessons learnt by the body (ie protein) cannot be
> transferred back to the genome (ie DNA). It is the antithesis to
> Lamarkianism. Epigenetic changes involve changes of the genome by the body
Epigenetic changes do not change the sequence of bases in DNA, and more
important I see no evidence that the body has learned any lessons. I see no
evidence that epigenetic changes are more likely to happen in the direction
of greater adaptability rather than the reverse. All I see is the
environment causing random changes in hereditary factors that, like all
changes, are more likely to be harmful than helpful.
> > How significant epigenesis is to evolution is another matter, of course.
Well Darwinian Evolution was what we are talking about! At most all
epigenesis does is provide a new source of variation for Darwinian Natural
Selection to work on; and if those changes don't persist through many
generations then epigenesis can't even do that.
> Obviously, there is no equivalent central dogma in cultural evolution.
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.
The discovery of epigenesis does not in any way challenge the central dogma
John K Clark
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