How does cloning work?

The nucleus from a mature, unfertilized egg, containing a single set of genes from the female, is removed and discarded.

It is replaced with an adult somatic (body) cell from the donor animal, containing two sets of genes (one from each of the donor's parents).

Following the application of an electrochemical stimulus, the egg/cell "couplet" fuses, and the resulting clone embryo begins to divide like a naturally conceived embryo.

After a brief period of growth in culture, the embryo is transferred into a recipient (a female of the same species, generally in estrus or hormonally-stimulated) as in conventional embryo transfer.

After the natural gestation period for that species, she will give birth to an animal that is genetically identical to the donor animal.

FDA News Release, December 28, 2006

Cloning Myths, FDA

Biotechnology Industry Organization

Center For Food Safety