Cloning

Nearly all living organisms have parents in which they were reproduced and born through various stages of the life cycle. Whether it is a human being with a mother and a father or a chicken hatching from an egg, most living organisms have male and female parents. Some living organisms also form from one parent such as when a single-celled amoeba splits into two to reproduce offspring.

However, there is a process which is much different in producing offspring called cloning. Cloning is the process when scientists take DNA from an animal cell and then place it or implant it into an egg cell taken from another animal. Before placing though, the DNA from the cell receiving it is removed.

An example of cloning, which made history in 1997, was when scientists successfully cloned a sheep. The new sheep's name was Dolly, and she was not born in the usual manner. Instead, she became an exact copy of her mother, similar to an identical twin. It would be nearly the same as taking the DNA from the son of a mother, placing the DNA in the egg cell of another woman, but first removing the woman's own DNA, and then allow the growth of the new cell in the woman. Nine months later there would be an exact copy of the mother's son born to the woman.

In the case of cloning, a father is not needed. In the first successful cloning of an animal the DNA molecule had all of the information needed to create a clone, Dolly. The DNA molecules contains the genetic code, which is basically directions for the new offspring. Normally, a new organism gets half of this code from the father and the other half from the mother. When these two cells are joined together they divide millions of times and then grow into the millions of cells which form the body of the animal. Each cell of the body has a copy of the genetic code and all it would need is an egg cell to grow.

So with cloning one of those cells is used and then the cell is simply placed in to the egg cell of the carrier. In the sheep example, the carrier was a female sheep. For Dolly, a single cell was used from the udder of her mother. The DNA in her mother's cell was removed and then transferred to an egg cell of another sheep. About five months later Dolly was born without a father and a copy or clone of her mother.

Though no humans have ever been fully cloned, human embryos have been cloned. Currently it may not be taking place, but in the future it may happen, but today it is rare. In the movies about Jurassic Park, cloning took place to create the dinosaurs, though it was a fictional movie, much of the science behind the process can be real.

Though there are fully developed human clones, other fully developed animals have been cloned besides sheep. They include the rhesus monkey, pig, cattle, cat, rabbit, deer, horse, a few others, and of course mice. Cloning also involves many, many failed attempts before it becomes successful. For instance, Dolly the sheep was not born until after 276 failed attempts. The only true successful cloning takes place when identical twins are born, but they came from a father and a mother. The cloned animals may also experience health problems.

In summary, cloning is basically creating another organism without the father involved, and the clone is an exact copy of the mother with the same genetic code. However, if cloning ever became 100% successful, the clones may look alike, but it would not mean they would behave in the same way.




A: 1997
B: 1987
C: 1999
D: 2002

A: DNA cell
B: Skin cell
C: Sperm cell
D: Egg cell

A: The father's DNA must be included
B: The carrier's DNA must be removed
C: The cells must be an exact match between the carrier and clone
D: All of the above

A: Cells
B: Sperm cell
C: Genetic code
D: Egg cell

A: 3 months
B: 4 moths
C: 5 months
D: 6 months

A: Pig and cattle
B: Mice and rabbit
C: Giraffe and elephant
D: Human embryo and deer








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