Is Cloning a blessing in disguise.....
It is said, 'Its nature's law to change constancy alone is strange.' The probability factor took a back seat when Scottish scientists at Rosalin institute cloned the celebrity sheep 'Dolly'. The breakthrough that happened to take place in 1997, was targetted with a volley of questions on 'cloning' term assosiated with different processes for duplication of boiological material.
Cloning made Dolly's success is a truly remarkable one because it proved that the genetic material from a specialized adult cell, such as an udder cell programmed to express only those genes needed by udder cells, could be reprogrammed to generate an entire new organism. Before this demonstration, scientists believed that once a cell became specialized as a liver, heart, udder, bone, or any other type of cell, the change was permanent and other unneeded genes in the cell would become inactive. Some scientists believe that errors or incompleteness in the reprogramming process cause the high rates of death, deformity, and disability observed among animal clones.After much discussion, Dolly, the first mammal to be cloned from adult DNA, was put down by lethal injection Feb. 14, 2003 Although most Finn Dorset sheep live to be 11 to 12 years of age, postmortem examination of Dolly seemed to indicate that, other than her cancer and arthritis, she appeared to be quite normal.
Different kinds of cloning
Reproductive cloning is the most commonly talked about and generally gets much media attention.But apart from producing a genetic twin of another organism, cloning can be classified into 1) DNA cloning, (2) reproductive cloning, and (3) therapeutic cloning.
DNA Cloning or Recombinant DNA Technology
The use of different kinds of terminology 'DNA Cloning' 'recombinant DNA technology,' 'DNA cloning,' 'molecular cloning,'or 'gene cloning' all convey the same meaning as 'DNA Cloning'. This technology has had its presence as early as the 1970s, and it has become a common practice in molecular biology labs today. .Actually it refers to the transfer of a DNA fragment of interest from one organism to a self-replicating genetic element such as a bacterial plasmid. The DNA of interest can then be propagated in a foreign host cell. .
Reproductive cloning :creation of Dolly
Its is a breakthough technology used to generate an animal that has the same nuclear DNA as another currently or previously existing animal.
the celeb sheep, Dolly was created by reproductive cloning technology. In a process called 'somatic cell nuclear transfer' (SCNT), scientists transfer genetic material from the nucleus of a donor adult cell to an egg whose nucleus or its genetic material, has been removed. The reconstructed egg containing the DNA from a donor cell must be treated with chemicals or electric current in order to stimulate cell division. Once the cloned embryo reaches a suitable stage, it is transferred to the uterus of a female host where it continues to develop until birth.
Therapeutic cloning, also called 'embryo cloning,' is the production of human embryos particularly for use in research. The goal of this process is not to create cloned human beings, but rather to harvest stem cells that can be used to study human development and to treat disease. Stem cells are important to biomedical researchers because they can be used to generate virtually any type of specialized cell in the human body. Stem cells are extracted from the egg after it has divided for 5 days. The egg at this stage of development is called a blastocyst. The extraction process destroys the embryo, which raises a variety of ethical concerns. Many researchers hope that one day stem cells can be used to serve as replacement cells to treat heart disease, Alzheimer's, cancer, and other diseases.
Should humans be cloned?
Due to the inefficiency of animal cloning (only about 1 or 2 viable offspring for every 100 experiments)tanding about reproductive cloning, many scientists and physicians strongly believe that it would be unethical to attempt to clone humans. Not only do most attempts to clone mammals fail, about 30% of clones born alive are affected with 'large offspring syndrome' and other debilitating conditions.