Cloning

Today's technology develops so quickly that many impossible things become true; the cloning technology is the example. What is cloning? Cloning is a process used to create an exact copy of a mammal by using the complete genetic material of a regular body cell. Different from the common propagate, cloning need only one cell and without sex. In 1997, the great news shocked the whole world that the British scientists created a lamp named Dolly from a single cell, miraculously; the cell had been taken from the udder of adult sheep, which show the first cloning experiment was successful.

The history of cloning

About the cloning history, we trace back to 400 million years BC, the plants could clone themselves but not to long. The human found the cloning 200 years ago, the first person who did the cloning experiment is a German biologist named Han Spermann, he uses the egg white to clone chicken in 1938 but it was failed. Until 1981, Kal Illmensee and Peter Hoppe report that they clone normal mice and embryo cell; it was a huge progress of the cloning history. After 2 years, the embryologists in UAS first cloned the human's cells; they put 32 cells into a surrogate mother, and then have cloned 4 extra same cells. In 1997, Ian Wilmut and his colleague Keith Campbell cloned a new adult sheep called Dolly. (Will, April 2002) So human spends long time on cloning research.

The process of cloning

The cloning has two main parts, one is the plant cloning and the other is the animal cloning. One type of plant cloning naturally occurs when a plant grows a runner. The runner grows horizontally across the ground forming a carbon copy of that same plant at the end. Eventually the runner dies and the daughter plant is separated from the mother plant. Another is when you cut a branch or leaf off of a plant and plant it. It will grow another identical plant. That method is called a cutting. Such as stolon, it is a weak branch of a plant, when it falls over and the tip touches the ground. The tip swells and roots are formed so that growth in the plant can continue.

The other kind of cloning in animals is nuclear transfer cloning. Nuclear transfer is when the nucleus of one cell is implanted into another cell that has had the nucleus taken out. That is called embryonic cloning. (Will April 2002) This kind of cloning that created Dolly is when an adult animal is cloned. What happened in Dolly's case is that Ian Willmut and his team of scientists took a nucleus from a Finn Dorset sheep and substituted it with a nucleus of an egg from a Poll Dorset. Once the egg had developed to embryo stage it was implanted into a third breed of sheep a Scottish Blackface. Dolly came out 148 days later as an exact genetic copy of the Finn Dorset. The other important thing about Dolly is that her genes came from a dead sheep. The cells came from a frozen mammary gland. (William Science Report 2001)

The cloning debate

When the cloning technology improves so quickly, many scientists and doctors have different opinions, someone think it is good but someone think it is bad. Cloning can bring many benefits to the human, such as rejuvenation, helpful for Defective genes, Liver failure, Kidney failure and Leukemia. These disease are very different to cure, if we use the cloning technology we can change the Gene's DNA order, so we can save lots