- TOKYO (AP) -- Two special calves were born Sunday -- the first clones
from cells from an adult cow, Japanese scientists reported.
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- The unnamed twins were born exactly two
years after Dolly, the British sheep that made history by becoming the
first clone of an adult animal.
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- They are the second adult-animal clones
-- after Dolly -- and were produced by a similar technique, said Toyokazu
Morita, an official of the Ishikawa Prefectural Livestock Research Center,
190 miles northwest of Tokyo.
-
- "We have succeeded in producing
calves from adult-animal clones, meaning that we can produce calves exactly
similar to adult cows," he said.
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- Morita said the new technique would be
used to breed better cattle strains with higher-quality beef or greater
milk capacity.
-
- "I think it's a very important step
in the scientific process," said Caird Rexroad, assistant deputy administrator
for the U.S. Department of Agriculture's research service. "There
have been a few questions about Dolly ... and confirmation would be good."
-
- He said the Japanese success was significant
primarily because it cloned another species. "It suggests the technique
may be generally usable," Rexroad said.
-
- Another cloning expert, Robert H. Foote,
said, "I suppose you could say that if you can clone sheep and cattle
from an adult, then the probability of cloning an adult human being is
less remote."
-
- Foote, a professor of animal physiology
at Cornell University in Ithaca, N.Y., said the latest success has "substantial
significance."
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- Cloning an adult means scientists could
clone proved animals. For example, adult cows that produce more milk for
market could be chosen for cloning instead of relying on the relative uncertainty
of cells from a fetus, Foote said.
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- The cow cloning helps discount the possibility
that Dolly's success was the result of some unknown characteristic of sheep,
Foote said.
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- On Feb. 16, scientists in the United
States cloned a calf -- a Holstein named Gene -- but the animal's genes
originated in a cell from a 30-day-old fetus rather than an adult cell.
The following day, Dutch scientists cloned two calves using the same technique.
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- In the Japanese experiment, researchers
took cells from an adult cow and placed them in unfertilized eggs whose
own nuclei had been removed.
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- Then two artificially cultivated embryos
each were placed into the wombs of five cows last November, Morita said.
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- All five cows became pregnant and one
of them gave birth to the twins Sunday, though all were due Aug. 13, Morita
said.
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