From: Robert J. Bradbury (bradbury@aeiveos.com)
Date: Tue Oct 08 2002 - 22:03:52 MDT
For the sake of my clarity in discussing this I'm going to shuffle
the order of some of the response -- I hope people will not object.
On Tue, 8 Oct 2002, gts wrote:
> 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.
>
> ABSTRACT: D2 and D4 dopamine receptor polymorphisms and personality.
> Am J Med Genet 1998 May 8;81(3):257-67 (ISSN: 0148-7299)
Actually, I hadn't read this previously but I'm happy to see it
posted and referenced here -- I've been making similar arguments
for years (mostly from a "logical" framework) and its nice to see
some hard data coming along to back it up.
(If it isn't clear, my position would be that we non-trans-humans
*are* currently "largely" our DNA -- at least more than most people
would like to admit.)
While I don't think we disagree in an abstract sense --
we may however disagree at a semantic level or in the "devil
is in the details" of how things are actually implemented.
> That research alone is sufficient to
> prove my case that the information contained in our genes is
> indispensable to our personalities.
As humans are currently instantiated, yes -- genetic sequences
clearly play an important role in who we are. *But* based
on nutritional aspects alone -- I could deprive you of a few
essential vitamins or amino acids and I would have a significant
impact on your personality. (I'm fairly convinced that this
was the case with myself personally recently -- so arguing
it is entirely "in the genes" is going to be a hard sell --
I didn't change any of my DNA -- I simply fixed my nutritional
levels.)
So while I would agree that "genes contribute to personalies"
I'm rather reluctant to use the term "indispensable".
The reason (at least to me) is obvious -- I can run an atomic
level molecular dynamics simulation of the atoms in your body
and still get out the same "personality" (with no actual
"real" testosterone involved).
So long as a transhuman includes the functionality that
testosterone is supposed to perform (either as similar
or better "hardware" or completely artificial "software")
then I'm uncertain where there is a problem unless there
is some assertion that its hormonal "function" *cannot*
be performed by alternative systems. This is a systems
engineering problem.
Re:
> Robert J. Bradbury wrote:
>
[ regarding my discussion of the "state" information in cells ]
> I'd like to see some convincing empirical proof of this concept. I
> associate "cellular memory" with new age hocus-pocus.
Let me be clear that I'm not invoking anything "new age" (while
I may lean that way at times with respect to discussions of
spirituality -- I don't lean that way with my science.)
The "empirical proof" is easy to produce. Just go do a PubMed
search on the topics of membrane fluidity and lipid free radical
reactions. For many hormone-secondary messanger reactions to take
place the receptors have to diffuse and make contact with their
"partners" in the membrane. Stiffer membranes (depending on fatty
acid nutrients in the diet or cross-linking due to free radical
reactions and/or aging) *will* slow down the rate of protein
diffusion within the membrane. That will in turn slow down reaction
times, thought processes, recall ability, etc.
At least some of the changes in "personality" that occur with age
*don't* occur because our DNA is changing -- the occur because
the rest of the hardware isn't working as well as it once did.
There is "memory" in the cells entirely outside of the DNA.
One only has to look at tests of collagen crosslinking (a commonly
used measure of effective "age") to realize that not all proteins
are replaced so effectively that we have the machinery of a 10 year old.
> 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?
Wait a minute here -- there *are* cells in your body that are dividing
and constantly being replaced -- but they are surface cells. (View
the human body as a somewhat deformed doughnut -- all of the external
and internal "exposed" cells are replacing themselves.) All of the
rest of the cells (heart, other muscles, liver, kidney, pancreas,
brain) have *very* low turnover rates. Perhaps Anders who may be
more familiar with the literature could offer an opinion as to
the turnover rate for neurons. One probably has ~40 billion neurons,
the loss rate definitely exceeds the replacement rate, but the
replacements are probably only coming in at the rate of dozens
or hundreds per day (???). Neurons are designed to *not* die
and replace themselves -- otherwise you would lose your existing
knowledge base.
> As I wrote to Charles I am arguing only that our genes are indispensable
> if we hope to preserve our personalities.
I would be more comfortable with the claim that "the functions that our
genes perform are indispensable for our personalities".
> And let's not forget astrological sign. :-)
Now now now. I'm trying to uplift the general tone of the discussion
and using morter shells when cannon balls are sufficient isn't very
nice. :-;
> 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.
I would agree with the analogy that hormones are to a large degree
like neurotransmitters acting over a much larger distance.
> 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.
I'd go a little but further -- I think the neurotransmitter quantity
and quality may be heavily influenced by the area of the brain it is
in which probably depends quite heavily on the developmental DNA blueprint.
*But* the genome cannot encode the organizing of 40 billion neurons or
much less the neurotransmitter types and strengths at specific synapses.
The brain *has* to be somewhat self-organizing which means there is some
fraction of personality encoded in the structure and *not* in the genes.
So the glove on the table has a tag attached that says "Why cannot one
self-organizing collective be replaced with another self-organizing
(or even a predesigned) collective?
I cite -- "looks like a duck, walks like a duck, quacks like a duck".
Where is the proof that it isn't for all intents and purposes really
and truly a "duck"?
Robert
P.S. (Damien, I know if you read this you are squirming in your seat
with that voice in the back of your head screaming "But its not me!".
Byegones.... :-))
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