Another Cloning First
French scientists say they have successfully cloned rabbits from adult cells for the first time. Previous rabbit clones came from embryos.
A research team from France's National Institute for Agricultural Research outside Paris made the breakthrough, which follows the successful cloning of sheep, cattle, goats, mice, pigs and cats elsewhere.
The team produced six clones; four developed normally and two died. Two of the cloned offspring were later mated naturally, resulting in separate litters of seven and eight bunnies.
Scientists say cloning animals will help their understanding of human diseases by allowing them to target individual genes. Cloned rabbits are particularly useful because their physiology matches humans more closely than rats or mice.
"Cloning might seem rather redundant in view of the bunny's ability to reproduce by natural methods," said a report on the research published in the April issue of New York-based Nature Biotechnology magazine.
But "the possibility of targeting specific genes during the cloning process could markedly enhance the use of rabbits as models of human disease," it added.
Currently, rabbits - which are more closely related to humans than are laboratory mice - are manipulated to produce human proteins for therapeutic uses.
The team used the usual cloning method of injecting cells from an adult rabbit into an egg. The resulting embryos were reared by surrogate mother rabbits.
Jean-Paul Renard and his colleagues at the national institute said the discovery showed in theory any mammal could be cloned, as long as scientists adapted their methods to the physiological features of the egg and embryo.
Scientists previously cloned rabbits from embryos, which is generally easier to accomplish. Other mammals to be cloned include cats, sheep, cattle, goats, pigs and mice.
Unlike the first cloned mammal Dolly the sheep, or the first cloned cat cc, the rabbits were not given names.
A U.S. study published last month stoked debate over whether cloning is safe, or even if it produces exact copies, when it showed cloned mice became obese even when they did not overeat.