What is CloningQUESTION: What is cloning?ANSWER:
What is cloning to the layperson? Simply put, cloning means the creation of a life. Man creating human life through cloning is where the cloning debate becomes controversial in many categories. That created life has the exact DNA structure of the host from which the DNA was extracted.
What is cloning referring to when it occurs naturally? Identical twins are considered natural clones, because two identical life forms developed from one fertilized egg cell that divided into two separate life forms. This twinning procedure has also been successfully accomplished in the laboratories of science and placed into surrogate mothers.
What is cloning referring to when Somatic Cell Nuclear Transfer (SCNT) is used? This is the method that was used to create Dolly, the sheep. A somatic cell is a cell from any part of the body other than the reproductive cells. The nucleus is the portion of each cell that contains the DNA that makes each life form unique. The nucleus of the somatic cell is transferred to a donor egg cell in which the nucleus of the donor egg has been removed.
In the case of Dolly, the sheep, a somatic cell from an adult female sheep was isolated. Using the SCNT method resulted in an embryo developing from this nuclear transfer and was implanted into a surrogate female sheep, which was carried to term resulting in Dolly. And though Dolly's case was heralded as a great achievement, Dolly died soon after her birth. Scientists are not able to clone humans like livestock, yet. That ability if ever, is decades from happening.
What is cloning as related to reproductive and therapeutic cloning? Reproductive and therapeutic cloning starts the same way as the procedure used to create Dolly. In reproductive cloning, the embryo is allowed to live and carried to term. Therapeutic cloning as done with gene therapy necessitates the destruction of the life form at some stage of its development. Before the zygote or fertilized egg becomes an embryo, the gender of the human can be determined at four days.
Scientists are discovering new sources for adult stem cells
, which is the cell needed for medical and scientific research. Adult stem cells have been discovered in umbilical cord blood and bone marrow. The afterbirth from a woman delivering a baby is utilized in this type of medical research, as is the bone marrow from diseased and healthy patients to find cures for diseases. Using these resources can eliminate the need to destroy a life to retrieve adult stem cells from an embryo that has already formed the basics for a heart, blood circulation, brain, and nervous system.
Ethical scientists are comfortable with the use of these alternative sources for adult stem cells to avoid the need of destroying human life. Other researchers want to be able to take this science as far as they can go, as they tried with gene therapy to cure a rare liver disease in 1999 at the University of Pennsylvania. The patient died from an infection that resulted shortly after receiving doses of a gene therapy product. Gene therapy for humans was halted in the United States. Ethical researchers inform us that cloning and genetic therapy is years away from being safely performed on humans. The research continues.