Eric Burton wrote:
It's all a big vindication for genetic memory, that's for certain. I
was comfortable with the notion of certain templates, archetypes,
being handed down as aspects of brain design via natural selection,
but this really clears the way for organisms' life experiences to
simply be copied in some form to their offspring. DNA form!
It is scary to imagine memes scribbling on your genome in this way.
Food for thought! :O
Well, no: that was not the conclusion that we came to during this thread.
I think we all agreed that although we could imagine ways in which some
acquired information could be passed on through the DNA, the *current*
evidence does not indicate that large scale transfer of memories is
happening.
In effect, the recent discoveries might conceivably allow nature to hand
over to the next generation a 3.5 inch floppy disk (remember those?)
with some data on it, whereas the implication in what you just said was
that this floppy disk could be used to transfer the contents of the
Googleplex :-). Not so fast, I say.
Richard Loosemore
On 12/11/08, Terren Suydam <mmmmba...@yahoo.com> wrote:
After talking to an old professor of mine, it bears mentioning that
epigenetic mechanisms such as methylation and histone remodeling are not the
only means of altering transcription. A long established mechanism involves
phosphorylation of transcription factors in the neuron (phosphorylation is a
way of chemically enabling or disabling the function of a particular
enzyme).
In light of that I think there is some fuzziness around the use of
"epigenetic" here because you could conceivably consider the above
phosphorylation mechanism as "epigenetic" - functionally speaking, the
effect is the same - an increase or decrease in transcription. The only
difference between that and methylation etc is transience: phosphorylation
of transcription factors is less "permanent" then altering the DNA.
He also shed some light on the effects on synapses due to epigenetic
mechanisms. Ed, you were wondering how synapse-specific changes could occur
in response to transcription mechanisms (which are central to the neuron).
Specifically: "There are 2 possible answers to that puzzle
(that I am aware of); 1) evidence of mRNA and translation machinery
present in dendrites at the site of synapses (see papers published by Oswald
Steward or 2) activity causes a specific synapse to be 'tagged' so that
newly synthesized proteins in the cell body are targeted specifically to the
tagged synapses."
Terren
--- On Thu, 12/11/08, Ed Porter <ewpor...@msn.com> wrote:
From: Ed Porter <ewpor...@msn.com>
Subject: FW: [agi] Lamarck Lives!(?)
To: agi@v2.listbox.com
Date: Thursday, December 11, 2008, 10:32 AM
I
To save you the trouble the most relevant
language from the below cited article is
"While scientists don't yet know exactly
how epigenetic regulation affects memory, the theory is that certain
triggers,
such as exercise, visual stimulation, or drugs, unwind DNA, allowing
expression
of genes involved in neural plasticity. That increase in gene expression
might
trigger development of new neural connections and, in turn, strengthen the
neural circuits that underlie memory formation. "Maybe our brains are
using these epigenetic mechanisms to allow us to learn and remember things,
or
to provide sufficient plasticity to allow us to learn and adapt," says John
Satterlee, program director of epigenetics at the National
Institute on Drug Abuse, in Bethesda, MD.
"We
have solid evidence that HDAC inhibitors massively promote growth of
dendrites
and increase synaptogenesis [the creation of connections between
neurons]," says Tsai. The process may boost memory or allow mice to regain
access to lost memories by rewiring or repairing damaged neural circuits.
"We believe the memory trace is still there, but the animal cannot
retrieve it due to damage to neural circuits," she adds. "
-----Original Message-----
From: Ed Porter
[mailto:ewpor...@msn.com]
Sent: Thursday,
December 11, 2008 10:28 AM
To: 'agi@v2.listbox.com'
Subject: FW: [agi] Lamarck
Lives!(?)
An article related to how changes in the
epigenonme could affect learning and memory (the subject which started this
thread a week ago)
http://www.technologyreview.com/biomedicine/21801/
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