College
Station, TX (2/15/02)- Having already cloned cattle, pigs and
goats, researchers at Texas A&M University have moved on to house pets,
with the first successful cloning of a common house cat. The fact that the
cloned kitten was one of only 87 cloned cat embryos to survive underscores
obstacles still remaining in this area of research.
In a process similar to that used with clone star Dolly the sheep, the researchers
transplanted DNA derived from the nuclei of cumulus cells of a calico cat
into the empty (i.e. nucleus removed) egg cell of another cat, then transplanted
the embryo into yet another cat. Cats now join the list of animals that been
cloned by transfer of a donor cell nucleus into an enucleated ovum that includes
sheep, mice, cattle, goats and pigs.
Graphic: "CC"
the cloned kitty with genetic mother "Rainbow"
The one in eighty-seven success rate is comparable to that reported with
cloned sheep and cows. Genetic tests confirm that the kitten, now two months
old, is indeed a genetic copy of the original calico cell donor. Interestingly,
the kitten does not have the same coloring as the genetic parent, a fact the
researchers attribute to the play of dueling X chromosomes and developmental
factors outside the control of the nucleic DNA.
In a first, failed experiment, the researchers attempted to insert DNA derived
from the cheek cells of a male cat into donor eggs. When this didn't;t work,
they then tried using cumulus cells from a female cat. Cumulus cells are found
near the ova of female cats. That approach was much more efficient, leading
to success after only three tries.
"With each new species cloned, we learn more about how this technology might
be applied to improving the health of animals and humans," said Dr. Mark Westhusin,
the project leader.
"The knowledge we gain from cloning these animals could greatly affect several
areas of science and medicine. With each successful cloned species, we learn
more about cloning procedures and how to make the process more efficient,"
concurred H. Richard Adams, dean of the College of Veterinary Medicine.
Oddly
enough, the cloning of the first cat is the result of a wealthy dog owners
desire to clone a beloved aging pet dog. The wealthy sponsors are funding
something called the Missyplicity Project, in association with a company called
the Genetic Savings & Clone, Inc. The sponsors have ponied up $3.7 million
to clone their 12-year old mixed-breed dog, Missy (pictured, left). Cloning
a cat is considered to be somewhat simpler than cloning a dog.
left: Missy,
potential clone dog
Pet cloning opens up a new subsection in the thorny debate on the ethics
of cloning now raging at the highest levels of science and politics. Issues
include the ethical treatment of animals in research, not to mention the appropriate
allocation of research funding. The Missyplicity Project has established its
own code of ethics, which among other things mandates that all clones produced
by the company go to good homes and that the research not be applied in the
furtherance of cloning humans.
Dogged Determination
The company ultimately hopes to offer the public a commercial dog-cloning
service. In addition to producing genetic copies of favorite pets, the research
employed to produce CC could also lead to a better understanding of the reproductive
biology of pets.One potential use of the technology would be to replicate
exceptional dogs such as seeing eye dogs and search-and-rescue dogs. These
techniques should also prove useful in ongoing efforts to clone of endangered
species, the researchers say.
The research was scheduled to appear in the journal Nature
on February 21, 2002, but the journal was forced to publish the article early
after the embargo was broken by some media outlets.
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