> From: Sarah Marr <sarah.marr@dial.pipex.com>
>
> There will, I believe, come a point in my life when I choose to raise a
> child with a (female) partner of my choice; and it is highly likely that
> she will bear the child. This being the case, and my being
> spermatozoically-challenged (the current PC phrase, I suspect), does anyone
> have any hard facts about the possibility of my genes being used to replace
> those in the sperm of an anonymous donor, resulting in a child of which I
> am a true parent?
I'd say that the odds are very high that, with enough investment, this
would be possible without any massive technical breakthroughs.
HOWEVER, at the moment it would be damned expensive. For more on that,
see the bottom of the message.
The usual concept -- that of fusing egg cells or at least their
nucleii -- has been tried. It doesn't work.
Howver, the recent Scottish sheep cloning work leads to some hope in
this regard.
There are two parts required here -- conducting some sort
of artificial meiosis and recombination, and then getting the
resultant set of recombined genes into an ovum in such a way that you
start to get an embryo out of the process.
Now, I'm not sure how to do both of these, but we now know how to do
half of the problem for sure, and there is a possible way to do the
other half.
To do the recombination is fairly easy conceptually, although I don't
believe anyone has actually tried it in practice.
Although your chromosomes are usually floating about minding their own
business in an unravelled state, mitosis causes your chromosomes to
bunch up into nice easy parcels. With the aid of some fairly
conventional tools, it should be possible to physically extract
chromosome pairs from a cell in mid-mitosis, use enzymes to break
the centromeres, and extract one chromosome from each pair of a cell.
Then, given 23 chromosomes from you, and 23 from your partner, you
could conduct mix and match in the laboratory. Admittedly you don't
get crossover, but who cares? (As an aside, you could use this
technique to have a child of more than two parents -- even fourty six
parents.)
Now, the chromsomes have to be re-implanted in an appropriate somatic
cell so you can get growth and division so you have lots of cells for
the next step. Unfortunately, the one problem is that what you end up
with after nuclear reimplantation of the chromosomes isn't necessarily
a viable cell. To my knowledge, the experiment hasn't yet been done
(though it may have been). However, if you started with chromosomes
from two individuals from the same kind of somatic cell -- say
skeletal muscle cells -- and re-implanted into somatic cells of that
type from one of the individuals -- a viable cell might
result. Certainly getting this part to work is a matter for research,
but it isn't entirely outlandish to think that it could work.
Luckily, this is the only major problem. Given a cell of this type, we
know what the rest of the procedure has to be.
The other part of the problem is, of course, to turn the resultant
recombined cell into a viable embryo. Luckily, we've had a
breakthrough in this recently. One could presumably use the Scottish
method to induce a quiescent state in the somatic cells resulting from
the previous step, and then use the resulting nucleii for nuclear
implantation into an egg cell donated by either you or your partner.
(I would suggest that you not use a third party's egg cell if you want
for whatever reason to retain the "family mitochondrial
DNA". Admittedly this is merely a sentimental consideration, but is
that not, in fact, what this whole operation is -- a sentimentally
based attachment to one's own DNA?)
I'd say that none of this is beyond the realm of the near-term
possible, but it is all, as I've noted, frightfully expensive. I would
suggest, however, that as there are large numbers of women with
similar desires, that large scale fundraising might be possible for a
privately funded research and development effort on this, and that if
the research properly funded and organized, solid results might be
possible in only a few years.
I would very seriously suggest that you might want to begin organizing
in this regard before the idiots ban all research in this area --
whether you have a partner in mind for this or not.
Perry