Cloning. The word itself probably conjures images from a science fiction movie, in which an evil genius creates clones of himself. With an army of genetically-identical twins at his command, the mastermind then proceeds to take over the world!
But is cloning merely the stuff of movies? Or is the science behind it real? Exactly what is cloning and how can it be used in the real world? These are questions that scientists all over the world have been attempting to answer for years.
The subject of cloning hit the front pages of newspapers around the world in 1997 when scientists in Great Britain successfully cloned a sheep. Dolly the sheep, as she was known, was different from every other sheep that had ever been born before. How so? She was the twin sister of her mother and did not have a father!
Dolly's life began when a single cell was taken from the udder of her mother. Scientists extracted the DNA from that cell. DNA stands for deoxyribonucleic acid, and it contains the particular genetic code that is the unique blueprint for every living organism.
Each one of your body's cells contains DNA, and your DNA is unique, like your fingerprint, because it defines who you are apart from everyone else in the world. Once the DNA was extracted from the cell taken from Dolly's mother, it was then implanted into an egg cell taken from another sheep.
Before implanting, however, the DNA from the recipient cell is removed. Therefore, when the DNA from Dolly's mother was implanted into the recipient egg cell, it replicated to create more cells with the same DNA as Dolly's mother. These cells were then implanted into a sheep and Dolly was born: a clone of her mother and without a biological father.
This process that we call cloning actually has a scientific name: somatic cell nuclear transfer. And it's not quite as easy as it sounds. It took scientists decades to perfect the process that led to the successful birth of Dolly the sheep. Since that time, many other animals have been successfully cloned, including mice, cows, chickens, cats, deer, dogs, horses, mules, oxen, rabbits, and rats.
But why would they do this in the first place? Are they attempting to create a sheep army to dominate the world? Not quite! Many scientists hope that cloning technology can be developed to the point where human stem cells, considered the building blocks of the body, can be created in a laboratory.
Stem cells, when implanted into the body, can grow into just about any type of cell. Scientists believe stem cells might one day be used as part of treatments to cure diseases like diabetes and Parkinson's disease.
Of course, many people worry that scientists will perfect cloning to the point where it's possible to clone an existing human being. Experts note that modern science is a long way from being able to do such a thing. They also point out that creating a clone of an existing human being would not create a twin of that person.
Identical twins, despite sharing the same DNA, have unique fingerprints. If you've ever known a set of identical twins, you already know that they're not the same person. They have unique personalities and slight differences that make them grow into different people over time. Likewise, a clone of a human being would share DNA but have very different experiences that could turn the clone into a very different person over time!