From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Jan 10 2003 - 09:12:41 MST
On Fri, Jan 10, 2003 at 08:54:06AM -0600, Extropian Agro Forestry Ventures Inc. wrote:
> I've said this for years.
> All that "idle" dna in a human or other genome might be how "instinct"
> and even
> possibly active memory is archived.
No. As I memory researcher I have to put down my foot here :-)
The introns are mostly composed to my knowledge of transposable
elements, little more than devolved viruses or the equivalent of
"copy me!" signs. There is no evidence I know of for any
information being transcribed from them (beside the transponase)
in the brain.
While memory does have an interaction with DNA, it is through the
cascade neural activity -> protein phosphorylation ->
activation/deactivation of genetic switches -> protein synthesis
-> changes in the neuron. Very complex and interesting, but no
place for the idle DNA.
Instincts are very interesting firmwired sets of reactions (like
the common insect and snake phobias of primates or sexual arousal
when viewing appropriate secondary and primary sexual organs) that
somehow link rather complex perceptions to various drives. Beats
me how it is done, but there is definitely a genetic factor here.
But it seems rather unlikely this has anything to do with silent
DNA, rather with the active DNA.
Besides, apparently birds have little or no introns, but they
still exhibit plenty of insticts.
People once thought that memory was stored in DNA or RNA, and it
was a popular theory. The famous experiments with flatworms whose
memories seemed to be transferrable through eating appeared to
support this view. But they were flawed, and today the consensus
is that memory is stored in synaptic states, as ion and second
messenger concentrations (the shortest forms), protein
phosporylation states, protein concentrations and structural
changes.
There is some debate on how active memory (what I'm thinking about
*right now*) is stored. A popular idea is reverberatory activity
within network of connected neurons. This may be augmented by very
fast synaptic changes (see an upcoming paper by A. Sandberg on
this issue :-), but the evidence is still hazy.
To sum up, there is probably no Elder Eddas within our silent DNA.
I find it rather comforting.
> Nature never wastes resources.
Yes it does. Nature wastes a lot of resources when not wasting
them would be more wasteful. We do not absorb all the nutrients of
our food, we have a lot more neurons than we actually require for
function, most animal young get eaten or killed and plenty of
resources are wasted by birds in mating displays. In the first
example a less wastegul digestion would likely not be worth it
evolutionarily, since the extra energy and nutrient requirements
of a better gut would make the resulting organism less fit than
one with a worse but simpler gut. In the second example a less
redundant brain would be more vulnerable to damage; the optimal
amount of redundancy depends on the level of brain damage danger
in the environment, and that is estimated very roughly through
fitness. And so on. Nature is abundant and wastes a lot, because
it only deals with local maxima of fitness, fitness estimates are
very noisy and the environment changes in a complex fashion,
moving the maxima around. A nature that never wasted resources
would never bother with vertebrates.
> Bacteria that have high resistances to heat, radiation would make good
> extracorporeal data archives.
I wonder if they really would. The length of a typical bacterial
genome is around 1.8 million base pairs (H. influenzae), which
means one could get in around a megabit or so per strain. The
human genome is a few billion base pairs, so here we could
probably hide a few gigabits. But that is still less than is
stored right now on my hard drive, and far less than the tape
archive in the institute cellar.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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