With the invention of cloning, several important questions have arisen. There are many incorrect ideas of what human cloning is. Cloning is the creation of an organism that is an exact genetic copy of another. This means that every single part of DNA is the same between the two. Because of this definition, any identical twin could also be considered a clone. However, it is artificial cloning that has sparked the interest of scientists in our time.
There are three different types of artificial cloning: genetic cloning, molecular cloning and therapeutic cloning, but human and animal cloning is done through genetic cloning. Genetic cloning occurs when a body cell is taken from an embryo in an early stage of development. The nucleus is then transferred to an unfertilized ovum from which the nucleus has been removed. The daughter cells from the earliest divisions are removed, and grown in culture or implanted into host mothers. Genetically identical offspring to that from which the original cell was taken is then produced.
The first attempts at artificial cloning started at the beginning of this century. An embryologist named Adolph Edward Driesch allowed the eggs of a sea urchin to develop into the two-blastosphere stage (the early stage of embryonic development in humans and animals), and then he separated them by shaking them and then allowing them to grow. However, he couldn’t explain his experiments, so he gave up his study of embryology. Over the following years, many other scientists tried to duplicate Driesch’s work, but their attempts failed.
In 1962, a scientist named John Gurdon developed the method of "nuclear transfer". This is a two step process. First, he used needles and a microscope to suck the nucleus out from a frog. With the genetic material removed the frog’ cells would not divide or differentiate even when fertilized. That was no surprise, as a cell is nothing without its nucleus. Then Gurdon used the same equipment and skill to transfer the nucleus from a frog's gut cell into another frog’s cell. That's nuclear transfer, the transfer of a nucleus from one cell to another, creating a new cell with a different nucleus. Many of these new cells which Gurdon created divided just like a normal developing embryo, producing a ball of cells. And this ball of cells differentiated. Nerve, skin and blood cells appeared just as they would in a normal embryo. After a typical length of time Gurdon had made tadpoles. Because the tadpoles had all come from the gut cells of the same adult, they all had the same genetic material. So they were all clones, identical twins of each other. However, unlike normal identical twins they were made from differentiated cells.
More scientists continued on John Gurdon’s path by trying to clone frogs and other animals. A recent event in cloning occurred in February of 1997. A Dr. Ian Wilmut and his fellow scientists at Roslin Institute in Edinburgh, Scotland, announced to...