Реферат: Cloning Essay Research Paper CloningGenetic engineering altering

Cloning Essay, Research Paper

Cloning

Genetic engineering, altering the inherited characteristics of an organism in a

predetermined way, by introducing into it a piece of the genetic material of

another organism. Genetic engineering offers the hope of cures for many

inherited diseases, once the problem of low efficiencies of effective transfer

of genetic material is overcome.

Another development has been the refinement of the technique called cloning,

which produces large numbers of genetically identical individuals by

transplanting whole cell nuclei. With other techniques scientists can isolate

sections of DNA representing single genes, determine their nucleotide sequences,

and reproduce them in the laboratory. This offers the possibility of creating

entirely new genes with commercially or medically desirable properties.

While the potential benefits of genetic engineering are considerable, so may be

the potential dangers. For example, the introduction of cancer-causing genes

into a common infectious organism, such as the influenza virus, could be

hazardous.

We have come to believe that all human beings are equal; but even more firmly,

we are taught to believe each one of us is unique. Is that idea undercut by

cloning? That is, if you can deliberately make any number of copies of an

individual, is each one special? How special can clones feel, knowing they were

replicated like smile buttons. “We aren’t just our genes, we’re a whole

collection of our experiences,” says Albert Jonsen. But the idea, he adds,

raises a host of issues, “from the fantastic to the profound.”

When anesthesia was discovered in the 19th century, there was a speculation that

it would rob humans of the transforming experience of suffering. When three

decades ago, James Watson and Francis Crick unraveled the genetic code, popular

discussion turned not to the new hope for vanquishing disease but to the specter

of genetically engineered races of supermen and worker drones. Later, the

arrival of organ transplants set people brooding about a world of clanking

Frankensteins, welded together made from used parts.

Already there are thousands of frozen embryos sitting in liquid nitrogen storage

around the country. “Suppose somebody wanted to advertise cloned embryos by

showing pictures of already born children like a product,” says Prof. Ruth

Macklin, of New York’s Albert Einstein College of medicine, who specializes in

human reproduction.

Splitting an embryo mat seem a great technological leap, but in a world where

embryos are already created in test tubes, it’s a baby step. The current

challenge in reproductive medicine is not to produce more embryos but to

identify healthy ones and get them to grow in the womb. Using genetic tests,

doctors can now screen embryonic cells for hereditary diseases. In the not to

distant future, prenatal tests may also help predict such common problems as

obesity, depression and heart disease. But don’t expect scientists to start

building new traits into babies anytime soon. The technological obstacles are

formidable, and so are the cultural ones.

Copies of humans are identical, but are the people the same? Probably not. For

a century scientists have been trying to figure out which factors play the most

important role in the development of a human personality. Is it nature or

nurture, heredity or environment? The best information so far has come from the

study of identical twins reared apart. Twins Jim Springer and Jim Lewis,

separated at birth in 1939, were reunited 39 years later in a study of twins at

the University of Minnesota. Both had married and divorced women named Linda,

married second wives named Betty and named their oldest sons James Allan and

James Alan. Both drove the same model of blue Chevrolet, enjoyed woodworking,

vacationed on the same Florida beach, and both had dogs named Toy.