Embryo transplants

The most basic technique of animal cloning is shown in the diagram below.

Adult cell cloning

Dolly the sheep was the first mammal to be cloned. She was born in the UK in 1996 and died in 2003. She was produced using the nucleus from an udder cell, although other cells such as skin cells may also be used.

The method for adult cell cloning is:

1. The nucleus is removed from an unfertilised egg cell.
2. The nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell.
3. An electric shock stimulates the egg cell to divide to form an embryo.
4. These embryo cells contain the same genetic information as the adult skin cell.
5. When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.