Cloning and aging
Tony Csoka (csoka@itsa.ucsf.edu)
Thu, 27 Feb 1997 03:45:46 -0800 (PST)
I think the most important scientific implication from the recent sheep
cloning experiment is that the mammalian genome does not appear to
undergo irreversible changes as cells differentiate.
In other words, the actual DNA which was removed from the adult sheep and
implanted into the enucleated egg was completely intact.
These cloning experiments could be used to refute the somatic mutation
theory of aging. This states that aging is a direct consequence of
accumulated mutations in the somatic (non-germ line) cells of the adult
body. The DNA contained in the germ line cells (i.e testis and ovary) is
assumed to be highly protected from mutations, otherwise entire species
would age.
The recent cloning experiments suggest that DNA can be kept in
"good helath" without having to be confined to the germ line cells.They
also suggest to me that aging could be (at least in part) an epigenetic
phenomenon.
I wonder how many years the original DNA from the donor sheep could be
propagated in consecutive clones without going through the germ cells?
It could turn out to be many times the lifetime of an average sheep.
If we could find out how the cloning process is rejuvenating the DNA, we
could try to mimic the process without actually having to clone ourselves.
This would clear up a lot of the problems associated with identity etc.
which have been discussed on this list.
Tony Csoka