What Animals Have Been Cloned?

The first cloned animals were tadpoles, and were created in 1952 by Robert Briggs and Thomas J. King. But the world really sat up and took notice of cloning with the birth of Dolly the sheep in 1996. She was the world's first cloned mammal. Since then we've had a whole succession of animal cloning world firsts - that is the first successful birth of a cloned animal from a number of different species.

Cc the cloned cat - clawed her way into the headlines in 2002.

The world's first cloned rabbits came scampering into the world in 2002.

Ralph - the world's first cloned rat, created by researchers in France, and announced to the world in 2003.

Prometea - the world's first cloned horse, unveiled in Italy in 2003.

Snuppy - the world's first cloned dog, created by South Korean scientists in 2005.

All of these animals were created by the process of nuclear transfer - the nucleus of an adult donor cell is fused with an enucleated recipient egg. Then it's prompted to start growing into an embryo, usually by electrical stimuli. The cells divide and are then transferred into a surrogate mother.

There are probably hundreds of animal clones, that reflect around 20 or so animal species. It's difficult to get exact figures as laboratories don't have to register every animal they clone, but one thing is clear, the technology is improving, and has come along way since that first tadpole swam into view.

There are several reasons that scientists want to clone animals, and these include: preservation of species, biomedical research, harvesting organs for Xenotransplantation, and tastier food. Some companies are getting into the field of pet cloning, though like all cloning enterprises this is being met with a great deal of controversy, not least because some animal clones have died prematurely.

Interest in animal cloning has accelerated since 2008 when the US Food and Drug Administration (FDA) stated that food products from cloned cows, pigs, and goats are safe for human consumption. Whether consumers find cloned steaks, burgers, and bacon easy to swallow remains to be seen.