Meaning of Cloning
Cloning is the asexual production of an exact copy of an original. So, for example, cloning could be used to produce the exact copy of a single cell.
The cell copy would be identical to the first cell and would have exactly the same DNA sequence. In many cases, cloning has been used to reproduce type-specific cells.
In some cases, cloning of an individual organism, such as Dolly the sheep, has been possible.
Dolly the sheep was cloned in 1996.
Unlike reproduction which involves two “parents” such as male and female plants, cloning has only one parent. This is often used to breed certain plants.
Certain plants have undergone cloning processes for thousands of years, but they do not participate in the ethical debates surrounding the cloning of animals, and more particularly humans.
Reproductive cloning is the cloning of an entire organism.
For example, reproductive cloning of animals was first attempted in the 1950s. Most identify Dolly the sheep, cloned in 1996. Dolly’s father had DNA transferred into an egg from which the nucleus was removed. . This is called somatic cell nuclear transfer.
The cell was then treated with chemicals and stimulated to grow, so that an almost exact replica of the cloned sheep was born.
DNA cloning has been used in genetic engineering to create plants that offer better nutritional value.
In reality, Dolly was not an accurate clone of her father. She shared the same DNA, but some of the genetic material from the donor cell also became part of Dolly’s lineage. This is only .01% of Dolly’s DNA, but it makes a negligible difference.
Human cloning has not yet occurred.
The cloning that resulted in Dolly wasn’t exactly simple. In fact, it took 277 donor eggs and the production of 29 embryos before a live birth was achieved. Calf cloning experiments with somatic cell nuclear transfer have been successful less than 1% of the time.
However, the idea of cloning humans still remains. While many people feel that cloning human tissue, like organs for transplantation, can be of value, many others feel that cloning an entire human being is unethical.
Some religiously unaffiliated scientists also believe that the ethical issues that may arise from prolonging life through cloned tissue need further scrutiny.
From a moral point of view, a lot has to do with how some reproductive clones are made. An embryo, even when the sperm and egg are simply fertilized, is believed by many to be a human being and therefore should not be destroyed.
The experimentation of embryos to produce clones often results in the death of the embryo. Also, some believe that the cloned embryos could be used specifically to harvest body parts and then kill them.
Some further believe that harvesting stem cells from an embryo is also wrong, or that creating embryos for the purpose of harvesting stem cells is unethical.
Others argue that stem cell research may point the way to curing diseases for which there is currently no cure. However, it should be noted that fewer people are opposed to the idea of cloning a body part than a human being.
Others are concerned about the cloning of extinct or endangered animals. In fact, Michael Crichton’s novel Jurassic Park dealt with this subject extensively.
Especially since actual dinosaur DNA, in sufficient abundance to clone, has recently been found, some scientists are concerned about the environmental impact that could result from reproducing a long-dead species.
In some countries, stem cell research has stopped when it comes to cloning human embryos. Other scientists are investigating the possibility of finding stem cells in other places, such as in the umbilical cord blood of newborns.
It is suspected that some countries may be trying to clone a whole human being, but have not yet succeeded.
Although cloning is very much in the news, it is still an imperfect science with more failures than successes today. This suggests that scientists may not fully understand all the mechanisms involved in creating an exact copy of another organism.
With more research, these mechanisms can be understood and pave the way for the creation of clones. However, doing so is likely to result in ongoing controversy.
In cloning, the cell must have the exact same DNA sequence.