4.4: Genetic Engineering and Biotechnology Cloning: producing identical copies of genes, cells or organisms. Clone: a group of genetically identical organisms or a group of cells artificially derived (made using lab techniques) from a single parent cell. Reproductive Cloning: very useful if an organism has a desirable combination of characteristics and more organisms with the same characteristics are wanted. Therapeutic Cloning: Sometimes cloning is used to produce skin or other tissues needed to treat a patient.

4.4: Genetic Engineering and Biotechnology Cloning using a differentiated animal cell In 1996, a sheep by the name of Dolly was born. She was the first clone whose genetic material did not originate from an egg cell. This is considered reproductive cloning because it makes an entire individual. Here is how the scientists in Scotland produced Dolly: 1. From the original donor sheep to be cloned, a somatic cell (non-gamete) was collected and cultured. The nucleus was removed from a cultured cell.

4.4: Genetic Engineering and Biotechnology 2. An unfertilized egg was collected from another sheep and its nucleus was removed. 3. Using a zap of electrical current, the egg cell and the nucleus from the cultured somatic cells were fused together. 4. The new cell developed in vitro in a similar way to a zygote and started to form an embryo. 5. The embryo was placed in the womb of a surrogate mother sheep. 6. The embryo developed normally. 7. Dolly was born, and was presented to the world as a clone of the original donor sheep.

4.4: Genetic Engineering and Biotechnology

Cloning using a undifferentiated cells In some cases, scientists are not interested in making an organism but simply in making copies of cells. This is therapeutic cloning and its aim is to develop cells which have not yet gone through the process of differentiation. To start this, embryos must be used, because embryonic stem cells are needed. These stem cells have the capacity to turn into any type of human cells which can be used to replace tissues or even organs that have become damaged or lost in the patient. Because embryos are used, naturally there are ethical issues on this hot topic.

4.4: Genetic Engineering and Biotechnology Ethical issues surrounding therapeutic cloning PROCON Embryonic stem cells can be used for therapies that save lives and reduce suffering Every human embryo is a potential human being, which should be given a chance of developing Cells can be removed from embryos that have stopped developing, so would have died anyway More embryos may be produced that are needed, so some may have to be killed Cells are removed at a stage when embryos have no nerve cells and cannot feel pain There is a danger of embryonic stem cells developing into tumor cells