4.+Reproductice+cloning

In reproductive cloning, the DNA of an unfertilized egg is removed and replaced by donor DNA, obtained from cells from another individual.The egg starts dividing to generate new cells and form an embryo. After that the resulting embryo is implanted into a uterus of a surrogate mother. In contrast to natural reproduction, reproductive cloning does not create a genetically new and unique individual through the recombination of each chromosome set from each parent. So the new life is a clone of the donor (and consequently his DNA). Because of technical and biological problems the reproduktive cloning has high failure rates. In addition, the clones that do survive are in very poor health with many problems, including obesity, arthritis, infection, breathing problems and death at young ages. Scientists are actively working at these problems and possible reasons are beginning to emerge. Human reproductive cloning at this stage is considered unsafe because there is no reason why cloning of humans would be more efficient or result in fewer health problems or deaths than has been seen for reproductive animal cloning. There are also high risks for the mother, because she is carrying an insane overweight fetus and has a abnormal pregnacy. So I think reproductive cloning is a highly delicate issue because of the massive unknown parts of it. This part of cloning will be a chunk of work for scientists in the future. Reproductive cloning is also very controversial because of scientific and ethic reasons. It is not the only possiblility to use reproductive cloning for creating twins, but if this method is used, the created animal has the same nuclear DNA like the donor animal. With the method of reproductive cloning we are able to transfer the genetic material from the nucleus of a donor animal. This constructed egg is treated with chemicals or electric current to reach a cell division. When it then reaches a suitable stage, it is transferred to a female host where it is developing till it is born. A fact that isn´t very well-known is that this clone isn´t an identical clone because some materials come from enucleated eggs. Now we are able to create a complete new organism and are also able to repopulate endangered animals. On the other side we shouldn´t forget the risks of reproductive cloning. It´s not cheap and it is ineffcient. These animals are larger than others and often die young as a cause of a mysterious death. The reasons therefore are defects in the imprint of the DNA.

** Types of cloning **

DNA cloning = „ recombinant DNA technology“, „ molecular cloning“ or „ gene cloning“ In this type of cloning only the DNA of a cell is doubled. A small piece of the DNA strang is removed and combined with a plasmid which reproduces itself to create many copies of the same DNA code. This copied DNA can then be inserted in a foreign host cell.
 * 1. DNA cloning **



Reproductive cloning means to create an animal or an human that has exactly the same DNA as the donator. The first cloned animal was named Dolly. Once the cells start dividing and the embryo reaches a suitable stage, it is planted into the uterus of a female host where it develops until its birth. There is something strange in reproductive cloning because even though they have the identical DNA they don´t have to look identical.
 * 2. Reproductive Cloning **

Therapeutic cloning is almost like the reproductive cloning, except of the fact that the embryos are not allowed to develog completely. The purpose of this method ist to exract the stem cells from the embryos and study them.
 * 3. Therapeutic cloning **

SCNT (= Nuclear transfer for stem cells or somatic cell nuclear transfer)
__**How it works:**__

1. DNA-taking from any one cell (usually skin of muscle cells) Transfer into an unfertilized egg with the aid of a microscopic glass. Then it's taken into a culture dish. 2. Egg cells are able to divide rapidly and come together as blastocyst. After it's devision its center is taken away for growing an embryonic stem cell out of it.

These embryonic stem cells now contain the patient's DNA and can develop into ever sort of cell and tissue (Gewebe) without rejection.



__Ways to get compatible cells:__

One way to find compatible stem cells for a given patient is to establish banks.