Re: Epigenetics in the real world

rnorman wrote:
There is an individual here who often posts material claiming that
evolution works through epigenetic mechanisms rather than classical
genetic ones. While we can dismiss those arguments, we must be
careful not to throw out the baby with the bath water. Epigenetics
does have an important role to play in many phenomena.

One example of the importance of epigenetics is given by research
reported (F. Lubin) at the recent meeting of the Society for
Neuroscience. Here, DNA methylation is shown to be important in
modulating long lasting changes in behavior. An excellent description
is provided in the Dana Foundation publicatin "Brain Work" in an
article titled "Environment influences gene expression."
http://www.dana.org/news/brainwork/detail.aspx?id=14402
Yes, this is a sort of press release, but the Dana Foundation has a
good reputation for accuracy in reporting. This epigenetics acts
within one individual and within that one individual's lifetime and is
NOT passed down to future generations. However, it is a clear example
of how the expression of the genes can be modulated by factors outside
the genomic sequence. We also do know that DNA methylation can be
inherited to some extent and so provides a mechanism for generational
modifications, although there is no indication that such inheritance
can survive over an evolutionary time frame.

If you don't like press releases, see the research publication
Epigenetic Regulation of bdnf Gene Transcription in the
Consolidation of Fear Memory
Farah D. Lubin, Tania L. Roth, and J. David Sweatt
Journal of Neuroscience, October 15, 2008, 28(42):10576-10586
http://www.jneurosci.org/cgi/content/short/28/42/10576

and

Epigenetics in the Nervous System
Yan Jiang et al.
Journal of Neuroscience, November 12, 2008, 28(46):11753-11759
http://www.jneurosci.org/cgi/content/abstract/28/46/11753

DNA is not modified but epigenetics permits change to be passed down thru the generations in terms of the switches which turn the DNA on and off being affected.

And the current New Scientist on Darwin's Tree of Life and the horizontal movement of genes (as opposed to vertical) is something that needs much pondering.


--
Douglas Clark ..................... Bath, Somerset, UK ......
http://usergroup.plus.net .......... http://www.dgdclynx.plus.com

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Relevant Pages

  • Re: Genetic or Epigenetic: The Causal Basis of Evolutionary Change
    ... the same factor in its eggs in repeating cycles for  many generations.. ... *difference* existing outside the gene rather than a regulatory ... The notion of epigenetics can only be applied to changes that ... Certainly there is no reason to suspect that somehow the ...
    (talk.origins)
  • Re: Article: Whew! Your DNA Isnt Your Destiny
    ... DNA genome we must be able to unravel the epigenetics of people. ... Changes to DNA and its associated proteins can alter gene expression ... DNA methylation is a chemical modification of the DNA molecule itself; ...
    (sci.bio.evolution)
  • Re: Epigenetic Inheritance and Epigenetic Information
    ... without gene mutations (reversion rates to antibiotic ... Epigenetic inheritance based evolution ... definitions of the object of study of epigenetics but I will ... reared in, somewhat smaller than mules. ...
    (talk.origins)
  • Re: Epigenetics in the real world
    ... One example of the importance of epigenetics is given by research ... We also do know that DNA methylation can be ... Epigenetic Regulation of bdnf Gene Transcription in the ... phenomenon, although not for evolution. ...
    (talk.origins)
  • Re: Epigenetic Inheritance and Epigenetic Information
    ... without gene mutations (reversion rates to antibiotic ... consistent with an epigenetic inheritance mode of resistance). ... definitions of the object of study of epigenetics but I will ... reared in, somewhat smaller than mules. ...
    (talk.origins)