An epigenetic system controls expression of genes (Was Epigenetic information for.....

Discussion in 'Health and medical' started by Cncabej, Mar 9, 2004.

  1. Cncabej

    Cncabej Guest

    Mon, 8 March 2004 004:12 Peter F. wrote:

    "CNCabej" <[email protected]> wrote

    > I would rather say that there is one integrated control
    > system, with the
    CNS as
    > its controller that is limited by genes (G), as well by
    > numerous external
    and
    > internal stimuli.

    >I think that what you are expounding fits in somewhere at
    >the center of the most interesting and fascinating of all
    >fields of scientific inquiry.

    >(It makes me salivate without being able to chew and
    >swallow - but I still love it from a distance.;)<

    If this is really so (and I believe it is), is it not
    paradoxical that people here in sbe are showing so little
    interest for "the most interesting and fascinating of all
    fields of scientific inquiry"? I wonder whether you have an
    explantion.

    >However, even if the notion and embryonic theory of "the
    >histone code" might currently not catalyze conceptual
    >clarity or inspire further insight, I still think it is
    >generally so relevant to what is discussed here that you
    >ought to have at least given it a mention.

    >If only for sake of a good (comprehensively spread-
    >out) measure.

    "The histone code", if you mean the remodelling of the
    chromatin by acetylation/deacetylation of histones, is an
    essential part of the integrated control system, but it was
    not mentioned here because of lack of space. In principle,
    the expression of all housekeeping genes is related to that
    remodelling.

    The integrated (epigenetic) system of control is a
    hierarchic system where the chromatine represents a
    downstream element in the system. In a very simplified
    scheme upstream the chromatine are signal transduction pathways<----
    membrane receptors <---- their respective extracellular
    signals (protein hormones, growth factors, secreted
    proteins, neurotransmitters etc.)<--- hormones of the target
    endocrine glands<--- pituitary stimulating hormones <---
    hypothalamic releasing hormones <---- brain chemical signals
    <---processing of the internal/external stimuli. Downstream
    the chromatine ("the histone code") are transcription
    factors and genes.

    The epigenetic system of control, with the CNS as its
    controller, controls the function of all housekeeping genes,
    genes whose differential expression determines the type of
    the cell (even the so-called cell-cell interactions are
    interactions at the level of downstream elements of signal
    cascades ultimately originating in the CNS).

    The function of the integrated system of control, with the
    CNS as its controller, is to maintain the inexorably eroding
    metazoan structure at all the different levels of
    organization. This implies that the system

    1)is in possession of information on the "normal"
    physiological and morphological state.
    2) does monitor the state of the system (based on the
    pervasive presence of the neural tissue thoughout the
    animal body).
    3) processes the input and by comparing with the set points
    it establishes detects deviations from the norm.
    4) sends messages (in the form of signal cascades) to
    affected parts for restoring the normal state.

    Being in possession of information for the normal structure
    the integrated system is at the same time the epigenetic
    system of heredity as it is demonstrated by the fact that it
    regulates and controls

    5. The formation of the egg and sperm cells

    6. The placement of maternal cytoplasmic factors in
    the egg cell.

    7. The early embryonic development (which is regulated not
    by zygotic genes, but by maternal cytoplasmic factors)
    up to the phylotypic stage, when a functioning CNS
    first arises.

    8.The postphylotypic development, including the post-natal
    development (the

    All the above suggest that the genetic system of heredity,
    which is responsible for most of the hereditary characters
    in unicellulars, in metazoans is subordinate to the
    epigenetic system of heredity.

    If this is really so, how can one determine whether the
    evolution of genes is the cause or a consequence of
    evolution? Mary Jane West-Eberhard in her recently published
    book presents some curious arguments that genes in her
    expression are "followers not leaders" in evolution. While
    examples of inherited changes in morphology without changes
    in genes are known, does any one know an example of how a
    mutation in a gene brought about an advantageous
    morphological change in metazoans? If not, with H.F. Nijhout
    we all have to admit that genes do no more than producing
    chemicals (RNA and proteins).
     
    Tags:


  2. Peter F.

    Peter F. Guest

    "CNCabej" <[email protected]> wrote in message
    news:[email protected]...
    > Mon, 8 March 2004 004:12 Peter F. wrote:
    >
    > "CNCabej" <[email protected]> wrote
    >
    > > I would rather say that there is one integrated control
    > > system, with the
    > CNS as
    > > its controller that is limited by genes (G), as well by
    > > numerous
    external
    > and
    > > internal stimuli.
    >
    > >I think that what you are expounding fits in somewhere at
    > >the center of
    the
    > >most interesting and fascinating of all fields of
    > >scientific inquiry.
    >
    > >(It makes me salivate without being able to chew and
    > >swallow - but I still love it from a distance.;)<
    >
    > If this is really so (and I believe it is), is it not
    > paradoxical that
    people
    > here in sbe are showing so little interest for "the most
    > interesting and fascinating of all fields of scientific
    > inquiry"? I wonder whether you
    have an
    > explantion.

    The simple reason I can explain easily. The complex
    (complementary to the simple) reason I can explain with such
    a great difficulty so that you probably won't understand
    what I mean..

    When I look at your apparently favorite scientific topic I
    sense have spare capacity and such a restricted background
    of relevant topical studies/learning that almost all that I
    can do is to feel raw enthusiasm and awe rather than getting
    stuck doing any sort of intricate analysis. I probably don't
    have enough "lifetime learning-capacity" to grow into a
    reasonably insightful amateur at your field of study
    ('evolutionary cell-chemistry - or whatever it is called?).
    I belive the topic is hard for most of the others around
    here as well.

    The complex/hard to explain complementary reason is
    (perhaps) that a profound and potentially world-view
    upsetting insight, such as can intuitively be perceived to
    be promised by your topic, is too scary for deep down
    conservative people -- people whose scientific
    conservativism is but one of the side-effects of their
    reliance on our evolved AEVASIVE capacity for containment
    (and otherwise handling) of CURSES (a type of memories
    caused by SHITS type stressors).

    P


    >
    > >However, even if the notion and embryonic theory of "the
    > >histone code" might currently not catalyze conceptual
    > >clarity or inspire further insight, I still think it is
    > >generally so relevant to what is discussed here that you
    ought
    > >to have at least given it a mention.
    >
    > >If only for sake of a good (comprehensively spread-out)
    > >measure.
    >
    > "The histone code", if you mean the remodelling of the
    > chromatin by acetylation/deacetylation of histones,

    Yes that is what I meant.

    > is an essential part of the integrated control system, but
    > it was not mentioned here because of lack of space. In
    > principle, the expression of all housekeeping genes is
    > related to that remodelling.

    <snipped a great overview>

    > All the above suggest that the genetic system of heredity,
    > which is
    responsible
    > for most of the hereditary characters in unicellulars, in
    > metazoans is subordinate to the epigenetic system of
    > heredity.
    >
    > If this is really so, how can one determine whether the
    > evolution of genes
    is
    > the cause or a consequence of evolution? Mary Jane West-
    > Eberhard in her recently published book presents some
    > curious arguments that genes in her expression are
    > "followers not leaders" in evolution. While examples of
    > inherited changes in morphology without changes in genes
    > are known, does
    any
    > one know an example of how a mutation in a gene brought
    > about an
    advantageous
    > morphological change in metazoans? If not, with H.F.
    > Nijhout we all have
    to
    > admit that genes do no more than producing chemicals (RNA
    > and proteins).

    I perversely seem to enjoy, philosophically, (the fear) this
    threat of an impending paradigm shift provokes!

    %-)

    P
     
  3. Dkomo

    Dkomo Guest

    "Peter F." wrote:
    >
    > "CNCabej" <[email protected]> wrote in message
    > news:[email protected]...
    > > Mon, 8 March 2004 004:12 Peter F. wrote:
    > >
    > > "CNCabej" <[email protected]> wrote
    > >
    > > > I would rather say that there is one integrated
    > > > control system, with the
    > > CNS as
    > > > its controller that is limited by genes (G), as well
    > > > by numerous
    > external
    > > and
    > > > internal stimuli.
    > >
    > > >I think that what you are expounding fits in somewhere
    > > >at the center of
    > the
    > > >most interesting and fascinating of all fields of
    > > >scientific inquiry.
    > >
    > > >(It makes me salivate without being able to chew and
    > > >swallow - but I still love it from a distance.;)<
    > >
    > > If this is really so (and I believe it is), is it not
    > > paradoxical that
    > people
    > > here in sbe are showing so little interest for "the most
    > > interesting and fascinating of all fields of scientific
    > > inquiry"? I wonder whether you
    > have an
    > > explantion.
    >
    > The simple reason I can explain easily.

    So can I. Write so that people can understand you and there
    might be more interest. Avoid jargon and convoluted prose.

    [email protected]

    P.S. What the hell is AEVASIVE, CURSES, and SHITS? Are these
    supposed to mean something to the uninitiated?
     
  4. Peter F.

    Peter F. Guest

    Please insert a "no" to make it "_no_ spare capacity", as per below:
    "Peter F." <[email protected]> wrote in message
    news:c2l3qo$23a1

    > When I look at your apparently favorite scientific topic I
    > sense have _NO_
    spare
    > capacity and such a restricted background of relevant
    > topical....
     
Loading...