Areas of Biotechnology Research

Reproductive cloning creates an individual with the exact same DNA as another individual. Cloned animals have been created by first removing the DNA from an egg cell. Then the DNA from a regular cell, one not involved in reproduction, is put in the egg. Researchers make the cell divide using chemicals or an electric current. Eventually, the embryo is put in a female animal, where it develops until it is born. The DNA donor and the clone are genetically identical; they have the exact same DNA. But a clone may not look or act quite the same as the donor because of differing environmental influences. Animals that have been cloned in recent years include sheep, cats, cows, mice, and pigs.

Reproductive cloning could be used to increase the numbers of endangered animals. It could also be used to bring extinct animals back to life if researchers are able to discover intact DNA from among their preserved remains.

Many people think that cloning is new. But humans have been cloning plants for thousands of years. If one cuts off part of a plant and puts it in water or fresh soil, it will often grow roots and begin to function on its own. The new plant is genetically identical to the original one. In addition, cloning of animals has been happening since the 1950s. The difference is that researchers now use adult cells instead of cells from embryos.

Therapeutic cloning is used to create embryos from which researchers can remove stem cells. Stem cells are cells that can become any kind of specialized cell, like heart, lung, or kidney cells. Stem cells could be used to grow new organs or replace diseased tissue. But stem cells are very controversial. Chapter 4 will talk more about them and the debate surrounding their use.