Cloning is the process of producing an exact genetic copy of an organism. The created copy is referred to as a clone. Although cloning can have therapeutic health benefits, it has been the subject of debate due to moral and ethical implications.
DNA Cloning
DNA cloning is also called recombinant DNA technology, or gene cloning. DNA cloning refers to the transfer of a fragment of DNA to a self-replicating genetic element. The DNA is then reproduced in a foreign host. Scientists can produce multiple copies of a gene using DNA recombinant technology. This type of cloning has been in use since the 1970s.
Reproductive Cloning
Reproductive cloning is a method of cloning that produces a whole creature, such as Dolly the cloned sheep. In reproductive cloning, genetic material is transferred from the nucleus of a donor cell to an egg in which the genetic material has been removed. Once the egg reaches a viable stage, it is implanted in the uterus of female host. Clones created in this manner are not exact replicas since only the nuclear DNA is the same as the donor.
Therapeutic Cloning
Therapeutic cloning produces human embryos used in research. Stem cells are harvested from the embryos to aid in treating disease. Stem cells can be used to develop any type of cell needed for the human body. Stem-cell research has been a topic of controversy due to the fact that harvesting of the stem cells destroys the embryo.
Uses of Cloning
DNA cloning is beneficial in the study and use of gene therapy and other technologies. Gene therapy can be used to treat genetic conditions by modifying the genes. Recombinant DNA technology is also useful in the genetic enhancement of crops and food sources. Reproductive cloning could be used to ensure the survival of animal species that are threatened or endangered. Scientists are interested in therapeutic cloning as a means to produce whole organs that can then be used to replace diseased or defective organs in human beings.
Risks of Cloning
According to the Human Genome Project, "cloning is expensive, highly inefficient and more than 90 percent of cloning attempts fail to produce viable offspring." Cloned animals often do not survive and those who do may be affected with "large offspring syndrome" or other debilitating conditions. Also, those who do survive may be affected with an unusually short lifespan. Perhaps, for this reason, gene cloning is the most common type of cloning procedure practiced. Reproductive and therapeutic cloning do offer potential benefits, but there is still much scientific knowledge to be acquired regarding these technologies.
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