From: rfd@po.CWRU.Edu (Richard F. Drushel)
Newsgroups: rec.arts.startrek.tech
Subject: Biology in TNG (was Re: ? about DNA and the little People)
Date: 23 Nov 92 19:12:51 GMT
Reply-To: rfd@po.CWRU.Edu (Richard F. Drushel)
Organization: Case Western Reserve University, Cleveland, OH (USA)
NNTP-Posting-Host: slc5.ins.cwru.edu


In a previous article, ACS110@psuvm.psu.edu () says:

>It is at least concievable that DNA sequences do actualy change
>durring a persons life. We have no knowledge of such an affect but
>then again we've never tried to look for it.

	The only instance I know of of somatic DNA loss as a cause
of differentiation is in the B-cells of the immune system during the
antigen-antibody response.  Antigen specificity is generated by the
rearrangement of the DNA sequence coding for immunoglobulins in
individual B-cells.  [Highly simplified.]

	Most experts prefer to believe that cell differention occurs
by sequential gene expression, *without* the loss of DNA sequences
used in the earlier stages of development.  That is, in principle,
genes needed only during embryogenesis are still present in the adult,
only strongly repressed so they can't be expressed out of sequence.
The data suggesting that DNA loss is not a general mechanism of
development is based upon *general* comparisons of the DNA content of
somatic cells versus those of the germ line (i.e. sperm and egg).  It
is quite possible that, when complete DNA sequences are available for
germ cells and various somatic cells (in maybe 50 years), there will
in fact be sequence differences due to deletion or rearrangement.

>Or it could be Trek-nobabble.

	The entire RVN business is indeed Trek-nobabble, inconsistent
with everything we know today about DNA-->RNA-->protein.  Better babble
would have been to invoke the derepression of early developmental genes.
But even this would not have magically transformed the adult bodies
into those of children.

	Which brings me to my biggest gripe about all the "rejuvenating"
capabilities of the transporter (as used in "Rascals" and on the aged
Dr. Pulaski)--according to the established principles of transporter
operation, *IT CAN'T HAPPEN*.

	Simply, the transporter scans and reconstitutes subjects at the
subatomic level, whether the subject is living or inanimate.  Living
beings are *NOT* reconstituted according to their *genetic* composition
(which is at the molecular and cell levels).  The DNA sequences are
*IRRELEVANT* to the materialization/dematerialization process.  The
transporter doesn't need a schematic circuit diagram of a tricorder in
order to beam it up!

	If some mysterious accident removed certain DNA sequences from
a person in transport, he would materialize as his normal-appearing
self.  It would take minutes, hours or maybe even days for metabolic
disturbances to appear--and these would *NOT* cause him to revert to
adolescent height, weight, or complexion (e.g. lack of wrinkles).  Very
likely he would just collapse suddenly and die.

	It is these fundamental misunderstandings of biology which make
me wince.  And spare me the argument that "Today's impossibility is
tomorrow's reality"--the details of DNA replication, protein synthesis,
and cell metabolism are established facts, just like earth gravity at
9.8 m/sec^2 or Planck's constant.  Extrapolate reasonably from what we
know--that is SF.  Inventing a hypothetical family of developmental
gene repressors is reasonable; throwing out 30 years of today's
molecular biology to invent a deus ex machina RVN due to ignorance
just cheats the audience.
-- 
Richard F. Drushel ****** Ph.D. in Developmental Biology as of 4:45 PM 9211.20
rfd@po.cwru.edu ** Cleveland FreeNet ** Co-Sysop, Coleco ADAM Forum ** Go Z80!
"The bright and blinding sunlight shines so hotly on the trash-heaps that mere
undigested food and snotty Kleenex flow as rivers of milk and honey." - c.5253
Newsgroups: rec.arts.startrek.tech