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Scientists examined cloned cells for a gene
which only appears if donor nuclei can reprogramme
themselves to develop as embryos rather than as
tissue cells. Only a third of donor nuclei showed
the gene at all. Many of those did not show it at
the right levels. Those cells either do not
develop or do not produce a normal embryo.
Experiments with mouse embryos, suggest that
one particular gene (the Oct4 gene) crucial for
early development is often not reprogrammed
properly during cloning. Its level of activity is
inappropriate for creating a new individual and
the cloning attempt fails. With one or two famous
exceptions (Dolly the sheep and CC the cat)
surviving clones are often short-lived and have
abnormal tissues. Though this single gene does not
explain every failure, it could account for as
many as 90% of failures.
CC the cloned kitten may have given pet owners
false hopes for re-creating deceased pets in the
near future. Cloning will never be an efficient
form of reproduction until scientists find a way
to reprogram genes vital for building a healthy
embryo.
Whether the cat fancy is ready for it or not,
experts believe that cat cloning isn't far away.
The first feline clone might be seen as early as
2001 according to Richard Denniston, president of
Lazaron Biotechnologies and a member of the animal
science faculty at Louisiana State University,
Baton Rouge, USA. Already, experts and researchers
from the fields of cell banking, cloning, tissue
culture and feline reproduction are working on cat
clones.
Will Pet
Owners Benefit?
The company which produced Cc (nicknamed
Copycat or Identicat by the media) could charge
wealthy pet owners thousands of pounds to
replicate animals which die. It could also be used
to replace socially valuable animals such as
outstanding guide dogs, search and rescue dogs or
transgenic animals such as pigs bred for organ
donation to humans. It is claimed that commercial
pet cloning will be the first breakthrough in
cloning technology to directly benefit the public.
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