Scientists in France successfully clone rat

By Associated Press, 9/26/2003

WASHINGTON -- Researchers in France have cloned the rat, overcoming a quirk in the rodent's physiology that has thwarted many earlier attempts to genetically duplicate the laboratory animal.

Both male and female white rats were cloned using a technique that slowed the maturing of the eggs used in the procedure, according to a report in the journal Science.

To clone the animals, the researchers had to expose the rat eggs to an inhibitor protein that slowed down the activation of the eggs. This allowed time for the scientists to remove DNA from the eggs and replace it with DNA from an adult rat cell.

The researchers said that in one experiment, 129 cloned embroyos were implanted in female rats and three male pups were born. One pup later died.