RE: [xmca] epigenesis

Okay... I seemed to have been able to somewhat answer my own question. I
found a website on DNA methylation:
http://www.nature.com/reviews/focus/dnamethylation/index.html and it has
quite a wealth of information, including the following:

Review
Nature Reviews Molecular Cell Biology 5, 148-157 (February 2004) |
doi:10.1038/nrm1312

Repairing DNA-methylation damage
Barbara Sedgwick1 About the author

Methylating agents modify DNA at many different sites, thereby producing
lethal and mutagenic lesions. To remove all the main harmful base
lesions, at least three types of DNA-repair activities can be used, each
of which involves a different reaction mechanism. These activities
include DNA-glycosylases, DNA-methyltransferases and the recently
characterized DNA-dioxygenases. The Escherichia coli AlkB dioxygenase
and the two human homologues, ABH2 and ABH3, represent a novel mechanism
of DNA repair. They use iron-oxo intermediates to oxidize stable
methylated bases in DNA and directly revert them to the unmodified form.

.... Also, there was an article that talked about the demethylation of
promoter DNA as a necessary step in the epigenetic reprogramming of
somatic cell nuclei. Nature Cell Biology 6, 984 - 990 (2004)
Published online: 26 September 2004; | doi:10.1038/ncb1176
DNA demethylation is necessary for the epigenetic reprogramming of
somatic cell nuclei
Stina Simonsson & John Gurdon

Thank you Martin... this is a fascinating area I hadn't looked into!
~ Emily

-----Original Message-----
From: xmca-bounces@weber.ucsd.edu [mailto:xmca-bounces@weber.ucsd.edu]
On Behalf Of Emily Duvall
Sent: Saturday, October 27, 2007 12:05 PM
To: eXtended Mind, Culture, Activity
Subject: RE: [xmca] epigenesis

HI Martin and all,
Please forgive me for not following all this - the defense is coming up
- but could I get a little more information on the PBS documentary? I'm
particularly interested in the idea the PTSD could be 'inherited'. I
know that the change in the physiology/chemical make-up of my husband's
brain (he was in recon, in Viet Nam) is something that the PTSD
treatment folks at the VA have emphasized. I hadn't thought about this
at the molecular level in quite this way, however. I would be very
interested in learning more about this.
I'm also thinking about this in terms of the child-soldiers.
You mention the methylation of the DNA - I know very little about this,
but can the sheath be regenerated?
~ Emily

-----Original Message-----
From: xmca-bounces@weber.ucsd.edu [mailto:xmca-bounces@weber.ucsd.edu]
On Behalf Of Martin Packer
Sent: Saturday, October 27, 2007 11:32 AM
To: eXtended Mind, Culture, Activity
Subject: Re: [xmca] epigenesis

Paul,

The PBS documentary includes discussion of a retrospective analysis of
data
over at least 3 generations in a relatively isolated Scandanavian
community:
in particular, records of births and deaths (with cause of death) and
annual
harvest yields. The focus of the documentary was not merely on the
epigenetic pathways of individual development (e.g. that genetically
identical twins diverge in their patterns of gene expression over the
years), which is a notion that's been around for a while, but on
mechanisms
of *inheritance* of epigenetic pathways. So post-traumatic stress in one
generation may well be *inherited* by children and even grand-children.
To
my knowledge this is a new idea, and one for which the mechanisms are
now
being worked out (methylation of the DNA, I think).

Martin

On 10/26/07 1:49 PM, "Paul Dillon" <phd_crit_think@yahoo.com> wrote:
  
> I'm looking forward to learning mmore about the research in that field
by
> definition it would seem to require a study that tracked three or
more
> generations of families at both that genetic and socio-cultural levels
which
> is 90 years for humans populations. That's long after I'll be
following
> all of this. :)
>
> Paul
>
>
> Bruce Robinson <bruce@brucerob.eu> wrote:
>
> Paul Dillon wrote:
>> Jay,
>>
>> Any possible answer your question " . . . why is the model of
>> gene-determinism so appealing, almost a religion today, both among
molecular
>> biologists and the lay public? Why has it been so easy for the media
to
>> spread this gospel?"
> I was pleasantly surprised to hear human genome mapper (and would be
> privatiser) Craig Venter dissociate himself from crude genetic
> determinism in an interview he gave to the BBC Today programme. He
came
> out against the one to one 'a gene for...' idea, talked about the
social
> environment of development interacting with genetic tendencies and
being
> more important in a whole range of behaviour, as well as, in a comment
> on the Watson controversy, describing race as a social construct with
no
> scientific basis. So there clearly are exceptions. But I do accept
that
> genetic determinism is pervasive and think Jay is right to point to
the
> resulting fatalism about social inequality as a cause, perhaps less as
> an excuse for people to do nothing and more as a justification of why
> things are the way they are in the first place. This is not new - Marx
> pointed to Darwin's drawing on Malthus and his picture of nature
> reflecting the model of competitive capitalism.
>
> Bruce R
>> would seem to require an adequate theory of why any "knowledge
>> system/ideology" is dominant in a given society at a given time. From
the
>> perspective of the classic Marxist model, i.e., "dominance of the
ideas of
>> the dominant economic forces" , the dominance of the genetic metaphor
in
>> contemporary capitalist societies seems to provide a text book case.
The
>> primary client for the products of the bio-technology and
pharmaceutical
>> industries in which most geneticists is the health care industry (15%
of US
>> GDP) , then there's the GMO dominance in capitalist agriculture.
Along with
>> cybenetics , genetic technologies , suffuse the fabric of modern
economic
>> activity.
>>
>> But that's only a formal cause and although probably a necessary
condition
>> for the ideological dominance of some branch of knowledge, still
insufficient
>> to answer your question. I think one of the effective causes at the
>> psychological level , might have to do with the utopian futures
genetics
>> provides the "cult of eternal youth" , likewsie a root metaphor of
popular
>> consumer culture. The promised developments of genetic technologies
certainly
>> have that Utopian dimension, better futures quality that makes of
good
>> ideology.
>>
>> Paul
>>
>>
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Received on Sat Oct 27 12:26 PDT 2007