The cloning craze began in 1996, when scientists in Scotland astonished the world by announcing that they had successfully cloned an adult sheep. They called her Dolly.
A clone is a copy of another living thing. Instead of having two sets of genes, from a mother and father, a clone has genes from just one parent. Genes are the instructions inside cells that determine the traits of a living thing. All non-cloned, naturally created mammals, including humans, have genes from two parents.
Scientists hope that animal cloning will someday save lives. Cloned pigs could provide organs to transplant into humans. Cow clones could be used to make life-saving medicines. In addition, cloning may help to preserve some of the world's fastest-disappearing species.
Here are some other animals that have been created in a laboratory.
- In 1997, not long after Dolly was born, scientists in Oregon announced that they had cloned a pair of rhesus monkeys, named Neti and Ditto. The monkeys were created from DNA taken from cells of developing monkey embryos.
- Scientists in Blacksburg, Virginia, cloned piglets from an adult pig in 2000. They dubbed the newborns Millie, Christa, Alexis, Carrel and Dotcom.
- Also in 2000, Japanese scientists cloned a baby bull from a bull that was a clone itself. It was the first time a large mammal was re-cloned.
- In 2001 scientists in Italy produced the first surviving clone of a baby mouflon, an endangered wild sheep found in Corsica and in Cyprus.
- In February 2002, Texas scientists introduced the world's first cloned cat. They named her "cc," short for carbon copy.
- Scientists at the University of Idaho created the first clone from the equine (horse) family in 2003. Named Idaho Gem, he is the first cloned mule. He is the identical genetic copy of his brother Taz, a champion racing mule.
- Snuppy, an Afghan hound and the world's first cloned dog, was created by scientists in South Korea in 2005.
- In 2008, Snuppy and two other cloned Afghan hounds successfully bred a litter of ten puppies - this is the first successful breeding involving only cloned dogs. One puppy died, but the remaining nine are healthy.