Why do scientists clone?

Some scientists would like to clone endangered species to protect them from extinction. In order to practice the techniques, scientists have so far cloned non-endangered animals, namely, tadpoles, mice and even horses. It took thousands of attempts for these experiments to be a success.

Picture of Dolly the sheep

Dolly was a clone produced by reproductive cloning.

Probably, the most famous cloned animal is a sheep called 'Dolly'. She was produced by reproductive cloning but died aged six (half the normal age for a sheep) due to arthritis and a lung tumour.

Scientists clone cells in the laboratory using SCNT so that they can understand disease and test medicines. This is known as therapeutic cloning.

Cloning cells for untreatable diseases

One day, scientists hope that cloned cells will be used to treat serious diseases such as heart problems, diabetes and spinal injuries. Scientists hope to remove stem cells from a five day old cloned embryo and grow specific cell lines from them which may treat disease.

By cloning a person's own body cells, scientists hope that a cloned stem cell line will not be rejected by the patient receiving the cells. The genetic material will be identical to their own. Cloned cells may one day be used to treat a damaged heart or neurons.

Testing new medicines

Scientists test new medicines on cells taken from the embryos before trying the medicines on animals and real people.