Reproductive cloning means creating an exact genetic copy of an organism. This means that a cloned sheep would be a genetic duplicate of another existing sheep.

Genes are sequences of chemicals that help in producing proteins that make up your body. Different genes control different hereditary characteristics. Genes can be found in long, coiled chains called chromosomes. Chromosomes are located in the control center, or nucleus, of the cells in your body.


In sexual reproduction, a child gets half of his genes from the mother's egg cell and half his genes from his father's sperm cell:


Through combining of different genes, there is variation and much diversity among humans.

However, in cloning, all of the clone's genes would come from a body cell of a single individual, resulting in an exact copy:


One cloning technique is the somatic cell nuclear transfer (SCNT), shown above. First, remove the nucleus from a body cell, and remove the nucleus from a sex cell. Then insert the nucleus of the body cell into the egg from which the nucleus has been removed. The resulting cell is treated by chemicals or electricity to begin developing into an embryo. Once the cloned embryo reaches a suitable stage, it is transferred to the uterus of a female, where it continues to grow until birth. The result is an offspring that is a genetic duplicate of the animal from which the original body cell nucleus and sex cell were taken.

Any animal created using this nuclear transfer technology is not truly an identical clone of the parent animal. Genetically, the clone's chromosomal or nuclear DNA is the same. However, some of the clone's genetic material comes from mitochondria in the cytoplasm of the enucleated egg. Mitochondria, which are the power sources in a cell, contain their own segments of DNA. Acquired mutations in this mitochondrial DNA play an important part in the aging process.

Parthenogenesis is another cloning technique, shown below. This type of cloning requires an egg cell, complete with all its chromosomes, to be chemically or electrically induced to begin dividing.