Cloning Of Mammals From Body Cells example essay topic

The process of cloning is the process of using the genes of a being to create another being genetically identical to it. Cloning technology has been called the "forbidden fruit of biology" (Begley 54). For years, scientists have been trying to perfect the cloning technique. In Scotland, scientists at the Roslin Institute have finally succeeded.

Their success comes in the form of a Finn Dorset ewe named Dolly. Dolly is a clone. Now that the cloning of mammals from body cells has been accomplished, we are forced to consider what stand must be taken on the issue of cloning human beings, and also examine the effect of popular culture on our perceptions of cloning. Dolly's case is not the first example of cloning. A man named Hans Spemann first envisioned cloning in 1938.

He suggested transferring the nucleus of an embryo into another egg. As early as 1952, two scientists, Robert Briggs and T.J. King attempted what Spemann had suggested with a frog embryo and egg. Unfortunately, the frog egg did not develop. (Specter / Kolata) That same year, researchers in Pennsylvania cloned a live frog.

The technique used was known as embryo twinning, or causing the embryo to split apart. It is much easier to clone with embryonic cells. Much later, mammals such as sheep were cloned using this process. (Nash 64) In 1970, John Gurdon repeated the procedure suggested by Hans Spemann. This time, the experiment yielded partial success.

The tadpoles were born alive, but they died when they began to feed. He showed that transplanted nuclei reverted to an embryonic state. In the early 1980's, there was some controversy over the reported cloning of mice. Karl Illmensee and Peter Hoppe claimed that they had cloned mice from embryos. Other scientists tried to repeat their success, and they reported that mouse embryos could not be used for cloning after reaching the two-cell stage. The claims of Illmensee and Hopp were discredited.

(Specter / Kolata) In the 1980's, biologists at Allegheny University of the Health Sciences cloned tadpoles from the red blood cells of an adult frog. The tadpoles could swim and eat just like normal tadpoles. They grew hind limbs, but died halfway through metamorphosis. (Nash 64) In 1993, defective human embryos scheduled to be discarded by a fertility clinic were cloned.

Scientists teased apart the cells from seventeen embryos (each two to eight cells in size) and grew each cell separately, ending up with several genetically identical embryos. (Begley 54-56) In 1994, calves were cloned by Neal First from embryos that had grown to at least 12 cells in size. He pioneered the technique of starving the cells of nutrients to make them undifferentiated (chromosomes folds up so that only the parts needed to perform a particular cell's function are exposed). Dr. Ian Wilmut copied this technique in 1996, when he cloned sheep from embryo cells.

(Specter / Kolata) Dr. Ian Wilmut, the head scientist at the Roslin Institute near Edinburgh, Scotland, is Dolly's creator. He is fifty-two years old, and he makes $60,000 a year working at Scotland's top research laboratory. If his breakthrough yields commercial success, he only stands to make about $25,000 in royalties. He does not mind, because his true desire is to understand things.

Dr. Wilmut's goal is to produce livestock that serve humanity by producing proteins and providing superior milk, meat, eggs or wool. He has been involved in reproductive science for years. In 1973 he produced the first calf grown from a frozen embryo. This enabled cattle breeders to improve the quality of their herds by using surrogate mothers to breed more of the cows with the best milk and meat. Dolly was born conceptually in a bar in 1986, when Dr. Wilmut heard a rumor that a lamb had been cloned from an already developing embryo. This rumor was indeed true; Dr. Steen M. Willadsen had produced the first mammal clone.

He had attempted to clone three lambs. Two were born dead, but the third survived. His first success came in the forms of Megan and Morag, two clone sheep that Wilmut cloned from early embryos using the nutrient starving technique pioneered by Dr. Neal First. The two sheep now share a pen with Dolly. Megan has become pregnant (through natural means). Their success laid the foundation for Dolly's creation.

(Specter / Kolata) Dr. Wilmut and the other scientists at the Roslin Institute succeeded in cloning an adult mammal from one of its body cells. They created a clone of a Finn Dorset ewe. It is more challenging to clone an animal from a body cell than from an embryo, because an embryo is an unspecialized cell. A body cell is specialized; the chromosomes are folded, because only certain parts of it are needed to perform the function of that specific cell.

It has been a challenge for scientists to make the chromosomes "unfold", making the entire genetic code accessible. The first step in cloning is to take a cell from the animal to be cloned and get its chromosomes to unfold. In Dolly's case, the scientists used a cell from the mammary glands of a Finn Dorset ewe. In this cell, only the genes needed for mammary functions were active.

To unfold the chromosomes, and make all of the genes usable, the scientists put it in a culture with few nutrients. The cell was starved until there were no active genes. The second step is to obtain an egg cell and prepare it to accept the donor cell. The scientists at Roslin took an egg cell from a Scottish Blackface ewe. They kept it alive, but suck out the nucleus with the DNA. The empty egg cell still has the "cellular machinery" (Nash 64) needed for fertilization and production of an embryo.

The third step is to fertilize the host egg cell together. This is accomplished using two electric pulses. The first pulse fuses the donor cell and the host cell together. The second one fertilizes the egg. Then, clusters of embryonic cells are allowed to grow for a period of six days. In the next step, the cell clusters are implanted in the host mother.

The Roslin scientists implanted the cells into a Blackface ewe. The surrogate mother brings the fetus to term. Then, after a gestation period, the Blackface ewe gives birth to a Finn Dorset ewe that is genetically identical to the original Finn Dorset. (Nash 64-65) Now that cloning technology is a reality, how will it be used That is the question that has everyone worried. Whenever cloning is mentioned, people immediately worry about cloning humans.

Many nations of the world (including England, Denmark, Germany, Belgium, the Netherlands, and Spain) have already banned the cloning of humans. President Clinton has ordered a federal bioethics committee to report in ninety days on the ethics involved in the cloning of humans and give recommendations on possible regulations or possibly a ban on human cloning. (Begley 55) But it is unlikely that such bans will prevent the cloning of humans. If it is possible, someone will do it.

"Ban human cloning in America, as in England, and it will develop on some island of Dr. Moreau". (Krautha 61) Cloning has a lot of potential for good. An understanding of cloning can possibly help heal spinal cords, heart muscles, and brain tissues, which would not regenerate on their own. It has great potential for fighting cancer as well.

(Krautha 61) Talk about cloning inspires visions of cloning clinics where people go to order up clones of other humans. A person requiring donations of rare blood or marrow could have himself or herself cloned to get that needed donation. A brilliant mind in a terminally ill body could conceivable (though not likely) be saved through cloning. On the other side, someone could clone themselves out of pure ego. Or, in the most extreme situation, someone might clone another Hitler. (Kluger 69) People assume that the same mind would inhabit the new clone body.

This is not true, however. The brain is far too complex to be duplicated. With any other organ, there would be the slightest differences. But there is no real pattern in the construction of the brain; those slightest differences would make the brain drastically different.

Even if a brain were to be duplicated exactly, experience would lead to differences. Experiences make and break connections between synapses in the brain. Identical twins, nature's clones, have different brains and can be very different people. (Johnson) But remember still that experiences are often greatly affected by physical appearances.

(Wright 78) The fact of the matter, however, is that cloning of humans (from body cells) in the near future is highly unlikely. For one thing, the process is still extremely inefficient. The greatest success rate so far is one out of 277, and that one was Dolly. (Specter / Kolata) Embryologist Colin Stewart of the National Cancer Institute pointed out that the donor cell's genes do not turn on until the egg has divided three or four times, whereas those genes turn on after only two divisions in humans. This may be a major obstacle to the cloning of human beings. (Begley 55) Popular culture can be partially blamed for the disturbance that cloning has caused in the past six week.

When people think of clones, they think of the clone armies and clone monsters that they have seen in movies, literature, and television. In 1978, the movie The Boys from Brazil shows us the result of one man's plan to clone little Hitlers. In Jurassic Park, cloning technology brings back dinosaurs to be displayed in an island zoo. The beasts are freed, and they proceed to slaughter a group of park goers. In the X-Files episode "Eve", FBI agents are faced with psychotic clones. In Michael Keaton's Multiplicity, an average man, wishing there was more of him to go around, creates three clones of himself, but finds that he cannot deal with them.

Cloning in popular culture can be traced all the way back to Mary Shelley's Frankenstein. Although the monster in the novel, and in countless films, is not truly a clone, he represents the same thing: man's ability to recreate himself. Frankenstein's mistake (creating artificial life) leads to the loss of everything he holds dear, and he eventually has to destroy his own creation. (James) The monster in Mary Shelley's Frankenstein curses his creator and compares their relationship to that of God and Adam in the Bible. The monster tells his maker that creation should be left to God. Humans have been trying to refine the technique for many years.

The success of Dr. Ian Wilmut and his colleagues at the Roslin Institute in Scotland now forces us to face the moral implications of cloning humans, and to realize that the reality of cloning may be very different from what popular culture has shown us it will be.

Bibliography

James, Caryn. A Warning As Science Catches Up On Cloning. New York Times, March 3 1997, Fine Arts Page.
Johnson, George. Don't Worry. A Brain Still Can't Be Cloned. /Send In The Clones. New York Times, March 3, 1997, p.
1. Specter, Michael and Kolata, Gina. After Decades of Missteps, How Cloning Succeeded / After Many Years and Missteps, a Dazzling Cloning Breakthrough. Time Magazine-March 10, 1997, p.
60-72. - Krautha, Charles. Special Report on Cloning. Nash, J. Madeleine. The Age Of Cloning. Kluger, Jeffrey. Will We Follow The Sheep. Wright, Robert. Can Souls Be Xeroxed. Newsweek-March 10, 1997, p.