Cloning FAQs
1.) Is cloning "unnatural"?
Not at all - some organisms in nature only reproduce
using cloning - not only bacteria and yeasts, but also
larger organisms like some snails and shrimp. Because in
nature sexual reproduction is the only way to improve the
genetic stock of a species, most asexual species tend to
die off, but at least one - a shrimp called Artemia
perthenogenetica - has survived for at least 30 million
years. Many more species, including the aphid, reproduce
by cloning most of the time, only reproducing sexually
every few generations. Perhaps one day humankind may
follow their lead.
2.) Could clones be "farmed" to provide spare body parts
for their "parent" clone without problems of tissue
rejection?
Possibly, although we don't know enough yet to be
confident that rejection would be eliminated entirely. You
would also have to wait a number of years until the
clone's organs were mature enough to transplant, and of
course your actions would be highly illegal unless your
clone was willing to act as a donor as a clone would be
just as human as you or I. Even leaving aside the ethical
concerns, with the progress that is being made in
understanding and coping with tissue rejection, you would
be more likely to have a pig's heart in your future than a
clone's.
3.) Could people be cloned without conscious brains (so
their body parts could be harvested with fewer moral
qualms)?
No. For starters, whatever consciousness is, it doesn't
reside in any one brain structure or set of genes that
could be easily removed from the clone before or during
its development. Moreover, attempting to surgically or
genetically erase someone's "consciousness" is itself
morally dubious. It would also be hard to know if your
"technique" worked. A person can look and behave like a
mindless vegetable but have a very active mind--witness
the paralysed French writer, Jean-Dominique Bauby, who
dictated a 130 page novel by moving an eyelid.
4.) Could vital organs be grown using cloning without the
rest of a body?
Possibly--but nobody is even close to knowing how.
Contrary to scientists' expectations, the birth of Dolly
shows it is possible to reprogram the cell of an adult (or
at least its genome) so that it begins development all
over again. This newly discovered flexibility means it may
one day be possible to reprogram skin or blood cells so
that they grow into "spare part" tissues and organs,
rather than whole organisms. But the technical obstacles
will be huge.
5.) Could cloning be used to create "super warriors" or
super-intelligent people?
Possibly - though we don't yet know enough about
human genetics to do much "improving" of people. So far,
because of ethical concerns, geneticists are concentrating
on finding the causes of genetic diseases and then curing
them. While cloning makes it easier to meddle with
human and animal genes, even before recent discoveries
a considerable amount of genetic improvement of animals
was already taking place. A thoroughbred horse is
essentially genetically engineered, for example.
6.) Could cloning be used to save endangered species?
At the moment its success rate is very low (Dolly was
only cloned after 276 tries) but if this can be improved on
it might well turn out to be useful to increase the
population of hard-to-breed animals. Extinct animals (or
animals without females) would be more difficult. A
female can't normally give birth to an animal of a
different species, but it is not yet clear whether a female
of a closely-related species could give birth to a clone of
a different species.
7.) Could cloning help gay couples to conceive and make men unneccessary for procreation?
In principle, yes. Of cours a clone would have to be the identical twin of one or the other partner - it would be difficult duplicate any of the mixing of genes that occurs during sexual reproduction using cloning techniques.
8.) What about a Manhattan Project for human cloning?
Picture this. Dolly's birth is announced and the
world cheers.There are no doubts, no wariness on
the part of researchers, religious leaders, politicians
or the public. They speak with one voice:we want
human clones!
In response, nations unite to create a lavishly funded
International Institute on Cloning, charged with
copying adult humans as quickly and safely as
possible. Its first priority is to improve
cloning efficiency. Dolly took more than 400
attempts, including 28 miscarriages.Such a high
failure rate is unacceptable for humans.
One theory is that adult cells are more set in their
ways than,say, the cells of a fetus or an embryo,
which are easier to clone.Since the cytoplasm of the
egg does the reprogramming magic, IICcell
biologists try passing the nucleus of an adult cell
through not one egg, but two. They also try fusing
nuclei with less mature eggs, which typically stall at
the reprogramming step, giving extra hours in which
to remould the nucleus.
A second explanation for the inefficiency of current
cloning techniques is that most adult cells are
damaged beyond the egg's ability to repair them. As
a cell ages it collects genetic scars:its chromosome
ends shorten, and DNA mutations accumulate.
The damage may not be obvious. An udder cell would
function perfectly well no matter how mangled its
heart genes have become, because they are switched
off. But if the cell was used in cloning, the embryo
would develop cardiovascular problems and be
aborted.
To get to grips as quickly as possible with the
problem of genetic damage, IIC geneticists focus on
mice, reasoning that their genetic make-up is well
known, and it's possible to study several
generations in a matter of months. With those mice,
they identify the types of cells that are least prone to
age-related damage, and develop efficient new ways
to screen for genetic damage, and even to reverse it.
In another wing of the sprawling IIC, reproductive
technologists start on the human end of the project.
They offer women made infertile by defects in their
egg cytoplasm the option of having their egg's nuclear
material transferred into a donor egg with a healthy
cytoplasm,and then fertilised.
Meanwhile, IIC tissue engineers transfer the nuclei of
cells taken from patients with Parkinson's disease into
eggs that have had their own nuclei removed, so
creating an embryo clone. Every cell in the very
young embryo is pluripotent--capable of
generating any type of adult cell. They put the
embryo cells in a flask and try adding different
nutrients and growth factors at different times in an
attempt to grow new nerve cells. Once they
succeed,they will have a stock of healthy nerve cells
that are a perfect match for the Parkinson's patients
who donated the originals--ready to be transplanted
back.
So far the IIC team hasn't tried to create a human
clone that makes it to adulthood. But they are getting
a feel for nuclear transfer with human cells, the
technique that underpins cloning.It will stand them in
good stead come the fateful day when they make
their first attempt to copy a human.
Sources:
Question/Answer 1-7: New Scientist
Question/Answer 8: New Scientist
