Unit 1
Practical Introduction
In February 1997, a group of scientists in Scotland, led by Ian Wilmut, announced that, for the first time, they have cloned an exact copy of an adult mammal. The cloned baby lamb, named Dolly, has the exact genes as the adult sheep from which she was cloned. In other words, the two are identical twins; only Dolly is six years younger. The goal of embryologist Ian Wiimut is to develop a way to raise identical sheep that produce medications for humans. He also wants to use this technology to improve livestock. A week after Wilmut's announcement, scientists in Oregon disclosed that they have used a different technique to clone rhesus monkeys, primates that are close cousins of humans. These accomplishments triggered a world-wide debate: Should scientists be allowed to clone animals? Will humans be next? Is cloning unethical and dangerous? Or is it a valuable research tool? Read about the latest techniques, presented in this unit, then debate and decide.
Practical Discussion
The Cloning Technology
Together with your partner or in a small group of four or five people, use the following exercises as points of discussion about the cloning technology.
Decide which of the following scenarios associated with cloning you adore or detest. Give reasons.
1. Thanks to the cloning technology, experts have cloned four exact copies of you. Just before you head to the hospital for a physical checkup, you ask another you to attend a business conference. Meanwhile, a third you is out playing golf, while a fourth is helping your wife with housework.
2. Cloning from an already existing human will provide the opportunity for parents to pick their "ideal" child. They will be able to pick out every aspect of their child and make sure that it is perfect before they decide to have it. For example, they can choose their hair and eye color and build almost exactly by looking at the individual they were cloned from. Think about the possibilities: a whole team of Michael Jordans, a scientific panel of Albert Einsteins, a movie starring and co-starring Jackie Chen.
3. Cloning animals has tremendous potential for helping people. Cloned sheep, for example, could be used as living drug factories. Scientists could “engineer” sheep that produce drugs in their milk. And by altering the proteins on the surfaces of animal organs to make them more like human organs, scientists believe they may be able to create a plentiful source of organ donors for people.
4. Some fertility specialists argue that what makes cloning so significant is that couples who have difficulty conceiving a baby could make copies of themselves. And parents whose child has a fatal disease like cancer might be able to clone the child.
5. Some unscrupulous people take a sample of your hair and make a clone of you without your permission.
Practical Reading
TEXT A
Questions for Consideration
1. How much do you know about cloning? What do you think are the differences between cloning and other medical techniques?
2. Do you want to make a copy of yourself by using cloning technology? Why or why not?
Clone Ewe, But Not You
In the closing years of this millennium, a quiet British embryologist named Ian Wilmut set out to improve the productivity of farm animals and along the way set off a biological earthquake. The experiment he firmly pursued to get a cell from an adult mammal to behave like a cell from a developing embryo -had long since been given up at the major centers of scientific research. Even high school biology students knew that once a mammalian cell had differentiated, and was programmed by nature to be bone or nerve or skin, it could not be deprogrammed.
Yet Wilmut did it. From a single mammary cell, taken from an adult female sheep, he and his colleagues at the Roslin Institute cloned a sheep called Dolly and introduced her to a doubtful world in February 1997.
Perhaps it was his isolation in a quiet rural part of Scotland that permitted him to resist the objectors. Or perhaps it was the isolation of the remote field of animal husbandry that fostered his originality.
However, he seemed as surprised as anyone else that his modest and simple experiment, conducted with limited funding, should have as much impact on our sense of what it is to be human as anything since Adam and Eve. Wilmut wanted to use his cloning technology to improve livestock. Any experimentation with humans, he believed, should be kept strictly at the level of cells and proteins. "It would be morally unacceptable," he said, to use his technique to create a human clone.
That, however, was the very thing that caught the world's imagination. Human cloning! The stuff of science fiction seemed about to become reality. Even before other labs had confirmed Wilmut's discovery, a Harvard-trained physicist named Richard Seed declared his intention to clone humans for commercial purposes. Few scientists found Seed's words believable, yet his announcement laid out a soul-shivering truth. Medicine has a strong impetus to use this technology-for basic research, for new therapies, to provide solutions to infertility or to "replace" a dying loved one. But medicine is also bound by the traditional rule to do no harm, and so it takes on added challenges-such as whether clones will die young because of their older DNA or whether they will suffer the environmental mutations picked up during the life of their adult parent. Dolly shakes our ethical foundations, our social norms, even our religious beliefs. What is the role of clones in society? Can they become human slaves or organ donors? Who are their parents? Who is their family? Are they made in God's image or in man's?
Human cloning is too profound to be undertaken without the broadest possible understanding of its implications for our culture, our traditions, our values, our laws and the future of the human gene pool. But it's not easy to talk about Dolly in a world that doesn't share a uniform set of ethical values and where it often seems that anything goes. Israel, Australia, China and most European countries have prohibited human cloning. Other countries, like the U. S., have not.
What makes this challenge even more difficult is that Dolly is not terribly real for most people. The very strangeness of her origin makes it seem abstract and irrelevant to everyday lives. Perhaps, like nuclear warfare or human eugenics, the full meaning of cloning will be felt only when we get a taste of its abuse. Do we wait for the first human infant to be produced, in secret, by Richard Seed or someone like him? Ian Wilmut, the soft-spoken scientist who started this noisy revolution, says no. The father of three (one of them adopted), he speaks passionately of honoring the individuality of the child. Human cloning, he says, “should be banned."
Questions on the text
1. Is it still correct to say that once a mammalian cell has differentiated, and is programmed by nature to be eyes or nerve or bone, it cannot be deprogrammed?
2. What was the original purpose of Ian Wilmut when he was conducting the experiment concerning cloning technology? What is Ian Wilmut's stance on creating a human clone?
3. Who is Richard Seed? How do you comment on his intention to clone humans for commercial purposes?
4. What are answers with regard to the following questions raised in the article: What is the role of clones in society? Can they become human slaves or organ donors? Who are their parents?
5. How do you interpret this statement: "Perhaps, like nuclear warfare or human eugenics, the full meaning of cloning will be felt only when we get a taste of its abuse?"
Practical Group Role-Play
The World Health Organization has called for a symposium on the future of cloning. The top scientists of the world will be attending along with great minds in their respective fields. There are several renegade scientists who propose to proceed with their projects regardless of the laws or the opinions of their colleagues. Concern for the future of our world, and for the rights of these unborn clones, is the purpose of the symposium.
In a small group of five, role-play five participants at the symposium respectively. Before undertaking this activity, each student reads his/her own role -play card carefully.
A Genetic Scientist:
You have a team of young scientists that have spent the last two years researching the fundamental stumbling blocks that up until now have prevented the possibility of cloning a human being. You tell all the people attending the symposium that you and your team are confident that as a result of your tests it will now be possible to proceed with the next step which is cloning a human. You have been approached by one of the wealthiest men in the world, and he has promised to provide you and your team with all the funds needed to create a duplicate of himself. Regardless of the outcome of this symposium, you will proceed with your work even if you must finish your work outside the United States.
A Sociologist:
You are attending the symposium because you and your colleagues have some reservations about the social implications of human cloning. Many questions are not being addressed by the procloning forces. You believe that not enough criteria have been outlined. There can be many long -lasting effects to cloning, such as the ethics of creating clones just for organ transplants. Do clones have any rights or the same rights allowed by the constitution of the United States? Should guidelines be adopted to limit how many times one individual can be cloned? Should there be an age limit on the individual who is being cloned? What if five years later the clone dies? Especially since the clone is starting all over as an infant, and what if the baby doesn't behave exactly like the original? Will they "throw it away" and try again with another clone? Won't that possibility devalue human life?
A Protestant Minister:
You and your colleagues have valid concerns about the human cloning proposals. Since they are an imitation, will the clones have a soul, or what if we create a group of look-alikes that have no concept of the difference of right and wrong? What about the rights of the young clones? Will they be exploited as organ donors, or have their young bodies misused by large companies just for a profit? Americans as a nation consider themselves to be the most developed society, yet they have only seen fit to implement a moratorium on human cloning. Israel, Australia, China and the majority of European countries have already prohibited this practice. What if this technology is used negatively in other ways? For instance, what if the Pentagon decides to create an army of superior strength, and intelligence? Perhaps, the government will experiment on them like laboratory rats.
A Reporter for a Medical Journal:
You have followed the news about cloning ever since “Dolly" the sheep was cloned. You know that currently there are several obstacles to be overcome to clone humans. The most thrilling method of cloning and the most unlikely to occur is to clone an adult by taking cells from that adult. Popular wisdom has it that once the cell has been specialized and become a part of the brain, heart or liver, it is next to impossible to reverse it. Can the genetic code from the original cell be unlocked? If not, then human adult cloning will never happen. The symposium will have to address these issues, and any new developments in this exciting new field of science.
A Doctor in the Field of Infertility:
You have a large client base that is very interested in the possibility of raising cloned children. You already spend a significant amount of your time determining all the psychological factors that affect parents who want children, but for various physical reasons, can’t conceive. The various methods that can be used like drugs or surrogate mothers, offer solutions to the physical problems, however there still remains the big question. Are the parents emotionally stable enough to handle a child they desire? With cloning, however, there can be even more possible psychological problems that develop, and may lie dormant for years. Consider the scenario where a young couple cannot have a child. They decide, because it is the mother's infertility, their best option is to clone her husband. What will her feelings be toward her son in fifteen or twenty years when she sees a duplicate of the man she fell in love with? What about the parents of a child that dies by accident? Should they in their grief, be allowed to clone their lost loved one? What if the infant does not respond to them exactly like the original child?
TEXT B
Questions for Consideration
1. Have you heard about genetically modified food? Will you eat genetically enhanced food, say a genetically altered tomato as big as a water melon? Why or why not?
2. What do you think of the scientific fiction that a child born under genetic enhancement, has all the traits that his/her parents desire? Is it really desirable?
Scientists are Close to Cloning Humans
What a difference a year makes. A year ago this month, an astonished world caught its first glimpse of Dolly the sheep, the first animal cloned from a cell taken from another adult animal. With her came the intriguing, and frightening possibility of cloning humans, and a queue of scientists and ethicists declaring no interest in using the technology for such a purpose.
A year on, the scene is quite different. Dr. Richard Seed broke ranks last month and said he wanted to set up cloning clinics-and though most experts are skeptical that he can do it, there are plenty with the knowledge and experience who now not only say it is possible, but are experimenting in that direction.
For instance, some infertility centers in the United States who said last spring they would never clone now say that they are considering it. A handful of fertility centers are conducting experiments with human eggs that lay the groundwork for cloning. Moreover, the Federal Government is supporting new research on the cloning of monkeys, encouraging scientists to perfect techniques that could easily be transferred to humans.
Ultimately, scientists expect cloning to be combined with genetic enhancement, adding genes to give desired traits-which was the fundamental reason cloning was studied in animal research.
Only California has enacted a law making human cloning illegal, and those who are intrigued by the idea argue that it is no worse, morally, than creating custom embryos from sperm and egg donors. After all, it is an American tradition to allow people the freedom to reproduce in any way they like.
"From my perspective, it's just a matter of time before the first human is cloned,” said Dr. Steen Willadsen, a cloning pioneer who developed the fundamental methods for cloning animals. "It is not for me, as a person who invents techniques, to say how we should use them," said Dr. Willadsen.
Lori Andrews, a professor at Chicago-Kent College of Law and an expert on legal issues of reproduction, said she recently got a call from a British scientist who told her the same thing. Another doctor told her that "if any of my relatives got cancer, I would clone them" and use the clone as a bone -marrow donor to save the cancer patient's life.
"I absolutely think the tenor has changed,” said Professor Andrews. "People who said human cloning would never be done are now saying: ‘Well, the risks aren't that great.’ I see a total shift in the burden of proof to saying that unless you can prove there is actually going to be harm, then we should allow it," she said.
Cloning would be fundamentally different from ordinary reproduction. It would involve taking a cell from a living person, slipping it into an egg cell whose genetic material has been removed and allowing the genetic material of the adult cell to direct the development of a new embryo, then a fetus, then a person who is the identical twin of the person who provided the initial cell. It would allow a living person to be reborn, in a sense, only at a late time.
Scientists and infertility specialists envision certain specialized circumstances in which it might be acceptable to clone humans. Grieving parents may want to reproduce a terminally ill child. Or a woman may want a child but be infertile. Is it worse somehow for her to clone herself than to obtain an embryo made-to-order with donated egg and sperm, the kind that many fertility clinics already offer the infertile?
"In fact," said Dr. Joseph Schulman, director of the Genetics and IVF Institute in Virginia, “if a woman has no eggs and her husband makes no sperm, they might consider cloning both husband and wife”. "Then they could have one of each," said Dr. Schulman.
If they then used those cells to make clones, the clones would contain the added genes in every cell of their body. Already, two such experiments have been completed in animals, using cells from foetuses rather than cells from adults. Last summer, Dr. Kith Campbell of PPL Therapeutics in Roslin, Scotland, and Dr. IanWilmut of the Roslin institute in Edinburgh, the scientists who created Dolly, announced that they had made Polly, a cloned lamb whose every cell contained a human gene. Shortly afterward, US company ABS Global announced the birth of Gene, a calf that was cloned from genetically altered fetal cells.
With humans, predicted Dr. Lee Silver, a molecular biologist at Princeton University, the first genetic enhancements might be genes to protect against diseases, like an AIDS resistance gene or a gene to protect against Alzheimer's disease, both of which have already been identified. "In a sense, it would be no different morally from vaccinating a child for a disease,” Dr. Silver said.
As more and more people become knowledgeable about genes, other enhancements become possible.
Dr. Donald Wolf, a senior scientist at the Oregon Primate Research Center and the director of Oregon's only in-vitro fertilization center, at the University of Oregon, has two federal grants to study cloning in rhesus monkeys. One will involve cloning from the cells of an adult.
"We're pretty optimistic, "said Dr. Wolf.”We have every reason to think it will work." He explained that the National Institutes of Health, which gave him the grants, was interested in genetically identical monkeys for AIDS vaccine research and in clones of rhesus monkeys.
By cloning the animals, Dr. Wolf hopes to make enough of them for investigators to study the disease and its treatments. "But one consequence of the primate work," Dr. Wolf said, “is that it would establish methods that could be applied for the cloning of humans." "We are laying the groundwork," he said, “Society should think about the possible results of all this work sooner rather than later."
But some experts say the real question is not whether cloning is ethical, but whether it is legal. "The fact is that, in America, cloning may be bad, but telling people how they should reproduce is worse, "said Dr. Willadsen.
Questions on the Text
1. What difference does a year make? Is there still a consensus in scientific arena that cloning humans should be prohibited?
2. Are there many states in America which have enacted laws making human cloning illegal?
3. How do you respond to this statement: "It is no worse somehow for an infertile mother, who also wants to have a child, to clone herself than to obtain an embryo made-to-order with donated egg and sperm, the kind that many fertility clinics already offer the infertile.”
Practical Additional Reading
Dolly's False Legacy
The announcement in February 1997 of the birth of a sheep named Dolly, an exact genetic replica of its mother, sparked a worldwide debate over the moral and medical implications of cloning. Several U.S. states and European countries have banned the cloning of human beings, yet South Korean scientists claimed in December that they had already taken the first step. In the following essay for TIME, embryologist Wilmut, who led the team that brought Dolly to life at Scotland's Roslin Institute, explains why he believes the debate over cloning people has largely missed the point.
Overlooked in the arguments about the morality of artificially reproducing life is the fact that, at present, cloning is a very inefficient procedure. The incidence of death among fetuses and offspring produced by cloning is much higher than it is through natural reproduction-roughly 10 times as high as normal before birth and three times as high after birth in our studies at Roslin. Distressing enough for those working with animals, these failure rates surely render unthinkable the notion of applying such treatment to humans.
Even if the technique were perfected, however, we must ask ourselves what practical value whole-being cloning might have. What exactly would be the difference between a "cloned" baby and a child born naturally -and why would we want one?
The cloned child would be a genetically identical twin of the original, and thus physically very similar-far more similar than a natural parent and child. Human personality, however, emerges from both the effects of the genes we inherit (nature) and environmental factors (nurture). The two clones would develop distinct personalities, just as twins develop unique identities. And because the copy would often be born in a different family, cloned twins would be less alike in personality than natural identical twins.
Why "copy" people in the first place? Couples unable to have children might choose to have a copy of one of them rather than accept the intrusion of genes from a donor. My wife and I have two children of our own and an adopted child, but I find it helpful to consider what might have happened in my own marriage if a copy of me had been made to overcome infertility. My wife and I met in high school. How would she react to a physical copy of the young man she fell in love with? How would any of us find living with ourselves? Surely the older clone-I, in this case-would believe that he understood how the copy should behave and so be even more likely than the average father to impose expectations upon his child. Above all, how would a teenager cope with looking at me, a balding, aging man, and seeing the physical future ahead of him?
Each of us can imagine hypothetical families created by the introduction of a cloned child-a copy of one partner in a homosexual relationship or of a single parent, for example. What is missing in all this is consideration of what's in the interests of the cloned child. Because there is no form of infertility that could be overcome only by cloning, I do not find these proposals acceptable. My concerns are not on religious grounds or on the basis of a perceived intrinsic ethical principle. Rather, my judgment is that it would be difficult for families created in this way to provide an appropriate environment for the child.
Cloning is also suggested as a means of bringing back a relative, usually a child, killed tragically. Any parent can understand that wish, but it must first be recognized that the copy would be a new baby and not the lost child. Herein lies the difficulty, for the grieving parents are seeking not a new baby but a return of the dead one. Since the original would be fondly remembered as having particular talents and interests, would not the parent expect the copy to be the same? It is possible, however, that the copy would develop quite differently. Is it fair to the new child to place it in a family with such unnatural expectations?
What if the lost child was very young? The shorter the life, the fewer the expectations parents might place on the substitute, right? If a baby dies within a few days of birth and there is no reason to think that death was caused by an inherited defect, would it then be acceptable to make a copy? Is it practical to frame legislation that would prevent copying of adults or older children, but allow copying of infants? At what age would a child be too old to be copied in the event of death?
Copying is also suggested as a means by which parents can have the child of their dreams. Couples might choose to have a copy of a film star, baseball player or scientist, depending on their interests. But because personality is only partly the result of genetic inheritance, conflict would be sure to arise if the cloned child failed to develop the same interests as the original. What if the copy of Einstein shows no interest in science? Or the football player turns to acting? Success also depends upon fortune. What about the child who does not live up to the hopes and dreams of the parent simply because of bad luck?
Every child should be wanted for itself, as an individual. In making a copy of oneself or some famous person, a parent is deliberately specifying the way he or she wishes that child to develop. In recent years, particularly in the U.S., much importance has been placed on the right of individuals to reproduce in ways that they wish. I suggest that there is a greater need to consider the interests of the child and to reject these proposed uses of cloning.
By contrast, human cloning could, in theory, be used to obtain tissues needed to treat disorders such as Parkinson's disease and diabetes. These diseases are associated with cell types that do not repair or replace themselves, but suitable cells will one day be grown in culture. These uses cannot be justified now; nor are they likely to be in the near future.
Moreover, there is a lot we do not know about the effects of cloning, especially in terms of aging. As we grow older, changes occur in our cells that reduce the number of times they can reproduce. This clock of age is reset by normal reproduction during the production of sperm and eggs; that is why children of each new generation have a full life span. It is not yet known whether aging is reversed during cloning or if the clone's natural life is shortened by the years its parent has already lived. Then there is the problem of the genetic errors that accumulate in our cells. There are systems to seek out and correct such errors during normal reproduction; it is not known if that can occur during cloning. Research with animals is urgently required to measure the life -span and determine the cause of death of animals produced by cloning.
Important questions also remain on the most appropriate means of controlling the development and use of these techniques. It is taken for granted that the production and sale of drugs will be regulated by governments, but this was not always the case. A hundred years ago, the production and sale of drugs in the U.S. was unregulated. Unscrupulous companies took the opportunity to include in their products substances, like cocaine, that were likely to make the patients feel better even if they offered no treatment for the original condition. After public protest, championed by publications such as the Ladies' Home Journal, a Federal Act was passed in 1906. An enforcement agent, known now as the FDA, was established in 1927. An independent body similar to the FDA is now required to assess all the research on cloning.
There is still much to be learned about the biology associated
with cloning. The time required for this research, however, will also provide
an opportunity for each society to decide how it wishes the technique to be
used. At some point in the future, cloning will have much to contribute to
human medicine, but we must use it cautiously.
Practical Words
| 1. embryologist | n. 胚胎学家 |
| 2. disclose | vt. 透露 |
| 3. rhesus | n. 罗猴 |
| 4. primates | n. . 灵长目 |
| 5. fertility | n. 繁育力；生育性 |
| 6. unscrupulous | adj. 不讲道德的 |
| 7. ewe | n. 母羊；雌羊 |
| 8. millennium | n. 千禧年 |
| 9. differentiate | vt. 使分化 |
| 10. deprogramme | vt. 恢复原态 |
| 11. mammary | adj. 乳房的；乳腺的 |
| 12. animal husbandry | 动物饲养 |
| 13. foster | vt. 培养 |
| 14, originality | n. 创新精神 |
| 15. soul–shivering | adj. 令人心惊胆颤的 |
| 16. impetus | n. 推动力 |
| 17. ainfertility | n. 不育症 |
| 18. mutation | n. 突变体 |
| 19. gene pool | 基因库 |
| 20. eugenics | n. 优生学 |
| 21. abuse | n. 滥用 |
| 22. symposium | n. 座谈会；研讨会 |
| 23. renegade | adj. 背叛的 |
| 24. stumbling block | 障碍物 |
| 25. moratorium | n. 暂停 |
| 26. surrogate | n. 代理（人）；替代品 |
| 27. lie dormant | 潜伏着 |
| 28. intriguing | adj. 引起兴趣的 |
| 29. break ranks | 走出队伍；出列 |
| 30. embryo | n. 胚胎 |
| 31, tenor | n. 一般趋向 |
| 32. fetus=foetus | n. 胎儿 |
| 33. envision | vt. 想象；展望 |
| 34. made-to-order | adj. 定制的 |
| 35. foetus | n. =fetus |
| 36. vaccinate | vt. 给…接种疫苗 |
| 37. legacy | n. 传代物 |
| 38. replica | n. 复制品 |
| 39. nurture | n. 教养；培养 |
| 40. intrusion | n. 侵入；闯入 |
| 41. balding | adj. 成为秃头的 |
| 42. intrinsic | adj. 固有的；本身的 |
| 43. herein | adv. 据此看来 |
| 44. live up to | 达到；做到 |
| 45. diabetes | n. 糖尿病 |
| 46. champion | n. 奋斗；拥护 |
Copyright © 2005 SkyQuestCom.com All Rights Reserved