From: ingles@bluejay.engin.umich.edu (Ray Ingles)
Subject: Re: cloning in Where Late the Sweet Birds Sang
Date: Mon, 13 Apr 92 23:53:13 EDT
Organization: University of Michigan Engineering, Ann Arbor
Keywords: cloning clones social_implications


In article <1992Apr08.000700.49016@yuma.acns.colostate.edu>, bg413893@longs.LANCE.ColoState.Edu (Brian Grossman) writes:
> Hi all,
> 
> For my medical anthropology class I have to write a term paper.  I have
> secured permission to use the clone society described in Kate Wilhelm's
> _Where Late the Sweet Birds Sang_ so long as I can show that her
> extrapolation of cloning science is "reasonable".
> 
> The problems I find are these:  for each successive generation of
> clones there is a corresponding degeneration in fertility and mutations
> are increasingly prevalent.
> 
> At the fourth or so generation, fertility begins to rise but mutations
> make survival for any individual clone precarious.  (It sounds to me
> like cells are having a difficult time differentiating, leading to high
> incidence of cancer-like problems.  Perhaps this is also the cause of
> increased fertility?)  By the sixth generation, there is almost zero
> survival.

 Bear in mind that I'm an electrical engineer, not a molecular
bio major, but this sounds more like a plot device than genuine
science.
 Consider ideantical twins, which are for all intents and purposes
clones of each other. Would succesive generations of twins suffer
from these problems? I don't think so.
 However, there *might* be a way to work it.
 If you assume that the DNA for a clone is taken from the DNA
of an adult clone (I.e., Joe #1 is cloned, then DNA is taken
from Joe #2 and cloned, giving Joe #3, etc.) then it might happen
that way.
 DNA mutates constantly over a lifetime. DNA from Joe #2 might
well contain small differences from Joe #1, and Joe #3 would
differ still more from Joe #1. The later in life the DNA is
taken, the more the differences.
 Also, note that just taking the DNA in a skin cell and popping
it into a fertilized egg won't give you a clone. It will, assuming
it divides at all, give you a lot of skin. In the proceess of
differentiating into skin, certain parts of the DNA were "turned
off," as it were. To make a clone, the DNA would have to be
"reset" somehow to foetal DNA.
  If the "resetting" process, as a side effect, introduced
the occasional mutation into the DNA, then mutations would
accumulate, possibly fast enough to have the effects you
describe.
 However, if *I* were running a cloning businees, I'd keep
a lot of Joe #1 DNA around, and not take the stuff from
Joe #2 at all. Easily circumvents the whole problem, at least
until you run out of Joe #1 material.

> I have been able to find general references to "mutations" from what
> might be called data transmission problems.
> 
> What I need are specific references that address these generation
> problems.  Does anyone out there have the background for this, or does
> anyone remember running across any texts or articles that discuss
> something similar?

 As to actual *references,* I've nary a one. I know a person
with a Masters in human genetics, though, and I'll email her
and ask...

> Brian Grossman

Sincerely,

Ray Ingles                  || The above opinions are probably
                            || not those of the University of
ingles@caen.engin.umich.edu || Michigan. Yet.