Human cloning - can it work?

Dolly the sheep was the first succeccfully cloned mammal. Gradual improvements in cloning technology have enabled researchers to clone mice, cattle, goats, pigs, deer, rabbits, cats, mules, and horses.  Recent successes by South Korean researchers in generating stem cells from cloned human embryos have heightened concerns that human cloning is not impossible.

Even with recent technological advances, animal cloning is still extremely inefficient. For every 100 experiments, only 1, 2, or if lucky, maybe 3 appear to produce a viable offspring in surrogate mothers. While scientific explanations for these failures remain to be defined, many researchers think they represent nothing but technical hurdles that will one day be solved. Even then, its survival beyond the perinatal period is unlikely. These is no reason to believe that any different outcomes will occur if and when human cloning begins.

Scientists believe that the resultant cloning abnormalities are not traceable to the donor nuclei, but it more likely involves failures in genomic reprogramming. Genomic reprogramming in the natural way prior to embryogenesis, involves a stage of development of the egg and the sperm known as gametogenesis, which can take months to years to develop into a mature gamete. This process is sped up during cloning, and it takes only minutes to hours. The process of configuring the exact state of the inner workings of the cell including such complex processes as methylation of the DNA may not be correct for the development of the embryo. Methylation of DNA and other complex functions are now known to be essential to the correct functioning of each human cell, as they ultimately control gene expression. And thus successful cloning may be dependent upon the donated DNA being correctly altered to the state of an early embryo. It is thought by some cloning experts that failure of the nuclear clones to produce viable offspring is due to inappropriate reprogramming of cells, which leads to unregulated gene expression.

It is reasonable to conclude that future human cloning experiments will have the same high failure rates as animal clones. The possibility of performing prenatal genetic screening exists as a way to control quality. If these groups plan on using current routine prenatal diagnosis for the detection of chromosomal and/or other genetic abnormalities, they will not detect the types of epigenetic disturbances that may occur with cloning as there are no extra tools in the developmental pipeline to help improve detection. Research is ongoing to develop reprogramming of certain cells to turn into specific tissues types, which could regenerate nerves, muscles, and other cell types, alleviating Parkinson's, Alzheimer's, and heart disease among other chronic illnesses. There are many potential benefits of therapeutic cell cloning, and this research should not be jeopardized with human cloning activities.

Acknowledgement
http://www.ama-assn.org/ama/pub/physician-resources/medical-science/genetics-molecular-medicine/related-policy-topics/stem-cell-research/human-cloning.page

Why clone?

Have you ever thought what is it about cloning that is so important that scientists all over the world are still experimenting, up till today? Why do we have to clone things? Well, there's definitely a reason. 

One reason is to help those people who want a child but are unable to. Infertile couples are able to have a kid as reproductive cloning does not require the fusion of the sex cells.

Another reason that cloning can benefit us is that it can help treat diseases. Therapeutic cloning can be used to treat degenerative diseases like spinal cord injury, organ failure or the nervous system. It would be able to save so many people with diseases or injuries.

Cloning would be able to replace the defective genes in someone that causes illness to him or her. The defective can be replaced with healthy ones.

One other example is also the reason for cloning the famous Dolly the sheep. Dolly had been genetically modified to produce milk that contains a human protein essential for blood clotting and it can be given to humans whose blood does not clot properly. 

Cloned animals can also be used to test new drugs and treatments. It is very useful as cloned animals are genetically identical so the response to the drugs would be the same,  instead of using animals with all different genetics.

If cloning really becomes successful in the future, all the things listed above can be achieved and it can benefit us. However, although there are many benefits, there is also a number not-so-good points. There is also the issue of moral and ethical implications of cloning and some people are against the idea of cloning. I hope this has helped you to understand more about cloning and its benefits. 

Acknowledgements:

http://www.buzzle.com/articles/human-cloning-facts.html

http://www.genome.gov/25020028