From: gts (gts_2000@yahoo.com)
Date: Tue Oct 08 2002 - 20:19:50 MDT
Robert J. Bradbury wrote:
>>> I would say that "some" of that information is contained
>>> in our genes.
>>
>> Okay, then where is the rest of it?
>
> Its "state" information. All of the cells, not just the
> neurons contain some history of where they've been,
> what they've encountered, etc.
I'd like to see some convincing empirical proof of this concept. I
associate "cellular memory" with new age hocus-pocus. Among other
things, cells are constantly dying and being replaced by new cells. How
can the replacement cell get wind of the memories contained in its
predecessor?
However even if there is a part of the personality not under direct
influence of the genes, this fact alone would not make our genes
dispensable. You essentially agreed when you wrote in a previous message
that "The genes enable specific activities (at cellular or intercellular
levels) that certainly have an impact on personalities."
As I wrote to Charles I am arguing only that our genes are indispensable
if we hope to preserve our personalities. I am not arguing against the
possibility of other indispensable non-genetic factors that might also
exist. I would include "cellular memory" as one of those other possible
non-genetic factors that make up our personalities. And let's not forget
astrological sign. :-)
>> Every neuron in our brains contain our DNA. Every action of a given
>> neuron is under the control of the genetic material in the
>> nucleus of
>> that neuron, such that every thought is under the control
>> of our genes.
>
> I don't think this is an accurate picture -- the DNA is a
> blueprint for most or all of the structures in the neuron.
> But the primary actions" of the neuron (whether or not to fire)
> is "controlled" by the surrounding neurons.
I disagree with your wording here. Neurotransmitters work much like
endocrine hormones: after being released by the axon of a neuron they
then bind to their corresponding receptors on the dendrite or body of
the neighboring neuron. Genes influence the numbers and types of
receptors at the receiving neuron, as well as the quantity and types of
neurotransmitters released by the sending neuron. Genes encode the
instructions for the synthesis of both the neurotransmitters and their
receptors. Genes, (in response to hormones like Brain Derived Growth
Factor), also control the synthesis of the proteins necessary for
dendritic expansion, which we know occurs even in adult life.
Testosterone, by the way, inhibits neuronal apoptosis and could affect
personality in that way also.
You'll recall the research I posted in the motivation thread in which it
was discovered that a certain personality trait can be predicted
statistically by the polymorphisms of the dopamine receptor genes found
in the DNA of the test subject. That research alone is sufficient to
prove my case that the information contained in our genes is
indispensable to our personalities. I'll repost it here for others to
read:
ABSTRACT:
D2 and D4 dopamine receptor polymorphisms and personality.
Am J Med Genet 1998 May 8;81(3):257-67 (ISSN: 0148-7299)
Noble EP; Ozkaragoz TZ; Ritchie TL; Zhang X; Belin TR; Sparkes RS
Department of Psychiatry and Biobehavioral Sciences, University of
California, Los Angeles 90024-1759, USA. epnoble@ucla.edu.
The relationship of various dimensions of temperament, measured by the
Tridimensional Personality Questionnaire (TPQ), to polymorphisms of the
D2 dopamine receptor (DRD2) and D4 dopamine receptor (DRD4) genes was
determined in 119 healthy Caucasian boys who had not yet begun to
consume alcohol and other drugs of abuse. Total Novelty Seeking score of
the TPQ was significantly higher in boys having, in common, all three
minor (A1, B1, and Intron 6 1) alleles of the DRD2 compared to boys
without any of these alleles. Boys with the DRD4 7 repeat (7R) allele
also had a significantly higher Novelty Seeking score than those without
this allele. However, the greatest difference in Novelty Seeking score
was found when boys having all three minor DRD2 alleles and the DRD4 7R
allele were contrasted to those without any of these alleles. Neither
the DRD2 nor the DRD4 polymorphisms differentiated total Harm Avoidance
score. Whereas subjects having all three minor DRD2 alleles had a
significantly higher Reward Dependence 2 (Persistence) score than
subjects without any of these alleles, no significant difference in this
personality score was found between subjects with and without the DRD4
7R allele. In conclusion, DRD2 and DRD4 polymorphisms individually
associate with Novelty Seeking behavior. However, the combined DRD2 and
DRD4 polymorphisms contribute more markedly to this behavior than when
these two gene polymorphisms are individually considered.
-gts
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