How Cloning Works?

When scientists explain the practice of cloning livestock, they describe clones as genetic twins born at different times. Cloning companies say it is just another reproductive technology, such as artificial insemination.

Here is how cloning works:

Scientists take an immature egg, usually from a cow that went to the slaughterhouse, and remove the nucleus. They add DNA from a donor cow, often taken from the skin cell of an ear, and a tiny electric shock coaxes the egg to start dividing and grow into a copy of the original animal. The egg is then implanted into a surrogate animal for gestation and birth.

The first mammal cloned from an adult cell was Dolly the sheep in 1997. Dolly was euthanized in 2003 at the age of 6, well short of her normal lifespan, after developing a progressive lung disease.