MARGUERITE the calf, the first mammal cloned from a fetal muscle cell, is
dead. The French scientists who created her say that her death raises the
question of whether cloned animals have weakened immune systems.
Jean-Paul Renard of INRA, the French agricultural research agency, in
Jouy-en-Josas near Paris, told the world about Marguerite last month (This Week,
21 March, p 24). Her problems began shortly after her birth on 20 February, when
the stump of her umbilical cord became infected. The infection persisted, so she
was kept in an enclosure by herself and treated with antibiotics.
During the night of 25 March, however, Marguerite decided to try to join cows
in an adjoining pen. She succeeded, but only after jamming herself under the
narrow gap between the pen鈥檚 bars and the floor. As she struggled to get free,
she suffered severe trauma to her spine and thigh muscles. The umbilical
infection soon spread to the injured tissues. Despite more antibiotics,
Marguerite died on 4 April.
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Renard fears that the rapid spread of the infection may have been aided by
some immunological defect caused by the cloning process. 鈥淲e can鈥檛 rule out that
possibility,鈥� he says. 鈥淎nd we certainly want to find out.鈥� Full results from
Marguerite鈥檚 autopsy should be available in the next few weeks.
Narcisse, a bull cloned from fetal muscle cells and born 10 days after
Marguerite, is still healthy. He has been put in an improved enclosure to
prevent a repeat of the accident.