I decided to investigate the cloning-ban bills a bit further to see
if the people posting and the press were quoting things properly.
If you go to:
http://thomas.loc.gov/home/c107query.html
and enter the Word/phrase "cloning", you get a number of
related bills, and in particular H.R.1644.IH and S.790.IS.
Reading the text it looks like what they are trying to prevent
is several things:
(a) human asexual reproduction
(which clearly gets into a reproduction rights issue
for unpartnered individuals such as myself)
(b) the high miscarriage rates and potentially children
with genetic defects likely to be associated with
somatic nuclear transfer technologies.
(but of course to really reduce these you need to
outlaw sex completely since human miscarriage
rates are already high (perhaps 60+% of conceptions
I've heard quoted), and of course each of us has
5-10 genetic "defects", so you could argue they are
taking away the reproduction rights for some couples
that new technologies are enabling).
(c) use of the 'cloning' process to produce human tissues or organs.
Now, (c) is the one above that I would be most concerned about.
But in thinking a bit more, I don't think it is much of a show
stopper. Growing a complete human for an organ bank or a new
body for a brain transplant is going to require we figure
out how to (a) stop a brain from developing and (b) keep the
body alive long enough to grow it to an adult stage. I don't
see the information & technologies to do that developing
anytime in the near future. Alternately, you could want to
use the technology to grow a single organ rather than a whole
body, but this is going to require that you know all the
cellular signals to flip to send the embryo in that limited
direction. That information is accumulating rapidly but it
is probably going to be available for stem cells long before
it is available for embryonic cells. I suspect the zebrafish
genome project will need to be complete and a lot of work
on developmental biology will be required before we are able
to manipulate embryonic cells the way we currently manipulate stem
cells (if there are significant differences between them which
is a debatable point). My guess is that robust information in
understanding the signals involved in all the various tissue and
organ development paths is probably 5-10 years out, in contrast by
that time we should be able to make stem cells sit up and beg for dinner.
Now, what the bill does not prohibit, which is important, is
research into the understanding of the molecular signals
that allow the development of an "egg" cell or the signals
that the egg uses to cause the reversion of differentiated
cell into an embryonic cell (thats the real magic IMO).
One might be able to make an interesting argument that
in those cases where nuclear transfer into eggs is successful,
that the source cells are pseudo-stem cells. The original
methods used intestinal cells and the cells at the bottom
of the crypts in the intestine are effectively intestinal stem
cells. So it may be that the cases that don't work are
when you get a nucleus from a terminally differentiated cell,
while the cases that do work are when you get a pseudo-stem cell.
If so, this means there will be lots of room for improvement in
these methods once we can reliably identify pseudo-stem cells.
That will knock the reliability leg out from under the position
the bill takes.
If the pseudo-stem cell scenario is accurate, then dedifferention
isn't really occuring when these methods are used and it means that
"adult" stem cells should work perfectly fine for growing
all the organs (or babies) we want. The signals that direct the
growth and differentiation processes are rapidly being understood.
A large fraction of the genes that produce the various signals
have been in the databases of HGS, Incyte, etc. for 5-6 years,
and there were recent articles in Science on clever "transformations"
that can be used to direct stem cells into differentiated cells that
produce insulin. They've turned other types of stem cells into
neuronal cells and muscle cells I believe. What the general public
(and politicians) don't seem to understand is that each and every cell
in an adult contains the complete blueprint for manufacturing another
human if we can figure out how to flip the correct switches.
Now, how they will modify the bill when it becomes possible
to turn any adult cell with pseudo-stem-cell characteristics
into a totipotent embryonic cell (permitting asexual reproduction
without the need for an "egg") will be interesting question.
Given the difficulties in obtaining "eggs" (to my knowledge they require
some nasty hormone treatments and a surgical procedure to get them), it
is clear that for the lowest cost methods, one wants to eliminate
that part of the process, so there is a fairly large incentive for
scientists to work on this.
I don't see the bills on preventing "cloned" people from entering the
U.S. as one typically doesn't "import" people. It would potentially
ban the importantion of "cloned" organs. So sending your cells
offshore to be grown into an organ and then importing them back
into the U.S. seems out. But going offshore to get the organ
implanted and then entering the country seems possible.
Now, as pointed out in the previous article I mentioned --
http://www.nationalreview.com/kopel/kopel041601.shtml
it appears they are attempting to regulate cloning under
the "interstate commerce" powers granted to the Federal
government by the constitution. So it is questionable
whether the law would stand up to a court challenge.
Robert
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