Cloning animals
Animals have billions of cells. The nucleus of such a cell has genetic information called DNA. All the nuclei of an animal have the same information. But each cell only uses a part of this information in order to work properly. The other part of the DNA is not active. But because a single cell holds all the DNA of an animal, scientists can make physical copies of an animal from only one cell.
They transfer the nucleus of an animal’s cell into an egg cell of another animal. This egg cell has the same genetic information as that of the donor animal. The cell then grows into an embryo. Scientists must then activate the DNA that was not active in the parent cell. Otherwise a full organism would not develop.
Clones do not behave in an identical way – this is because they live in different environments. Researchers have found out that identical twins that carry the same DNA are different because they grow up differently.