官方APP下载:英语全能特训(微信小程序版,支持苹果手机、安卓手机)

创办于2003年
UNSV记不住?那就记中文谐音“忧安思危”吧!
  Slow and Steady Wins the Race!
UNSV英语学习频道 - Slow and steady wins the race!
公众微信服务号
英语全能特训(微信公众服务号)
UNSV英语学习频道淘宝网店
客服短信:18913948480
客服邮箱:web@unsv.com
初级VIP会员
全站英语学习资料下载。
¥98元/12个月

第3册 - Unit 8, Section A - Legal and Moral Implications of Cloning

阅读次数:


VIP会员专享下载:(非VIP会员无权下载!如果想下载,但还不是VIP会员,请点此订购
下载方式:使用鼠标右键(注意是鼠标右键!)点击下面的MP3音频/MP4视频链接,然后选择“另存为…”。
MP3节目录音 MP3节目录音 
文章正文
同步字幕

At first it was just plain surprising. Word last week that a scientist named Ian Wilmut had succeededin cloning an adult mammal - an achievement long thought impossible - caught the imagination ofeveryone. The laboratory process that produced Dolly, an unremarkable-looking sheep, theoreticallywould work for humans as well. A world with human clones was suddenly within reach. It was sciencefiction coming to life.

In the wake of Wilmut's announcement, governments hurried to draft guidelines for the unknown, afuture filled with incredible possibilities. President Clinton ordered a national commission to study thelegal and moral implications of cloning. Leaders in Europe, where most nations already prohibit humancloning, began examining the moral implications of cloning other species.

Like the Theory of Relativity, the splitting of the atom, and the first space flight, Dolly's appearancehas generated a long list of difficult puzzles for scientists, politicians, and philosophers. And wildquestions on the topic of cloning continue to mount.

Why would anyone want to clone a human being in the first place?

The human cloning situations that experts consider most frequently fall into two broad categories: 1)parents who want to clone a child, either to provide transplants for a dying child or to replace that child,and 2) adults who for a variety of reasons might want to clone themselves.

Will it be possible to clone the dead?

Perhaps, if the body is fresh, says one expert. The cloning method used by Wilmut's lab requirescombining an egg cell with the nucleus of a cell containing the DNA of the person to be cloned. (DNA is avery long, ribbon -like molecule that contains our genetic information.) And that means that thenucleus must be intact. Cells die and the cell nucleus begins to break apart after death. But, yes, intheory at least it might be possible.

Would a cloned human be identical to the original?

Identical genes don't produce identical people, as anyone who knows a set of identical twins can tellyou. In fact, twins are more alike than clones would be, since they have at least shared the sameenvironment within the mother, are usually raised in the same family, and so forth. Parents could clonea second child who resembled their first in appearance, but all the evidence suggests the two wouldhave very different personalities. Twins separated at birth do sometimes share personalitycharacteristics, but such characteristics in a cloned son or daughter would only be reminders of thechild who was lost.

Even in terms of biology, a clone would not be identical to the 'master copy'. The clone's cells, forexample, would have energy-processing machinery that came from the egg, not from the person whowas cloned. But most of the physical differences between originals and copies are so minor thatdetection of them would require a sophisticated laboratory. The one possible exception is bearingchildren. Wilmut and his coworkers are not sure that Dolly will be able to have lambs. They will try tofind out once she's old enough to breed.

What if parents decided to clone a child in order to harvest organs?

Most experts agree that it would be psychologically harmful if a child sensed he had been broughtinto the world simply as an organ donor. But some parents already produce second children withnonfatal transplants in mind, and many experts do not oppose this. Cloning would increase the chancesfor a tissue match from 25 percent to nearly 100 percent.

If cloned animals could be used as organ donors, we wouldn't have to worry about cloning twins fortransplants. Pigs, for example, have organs similar in size to humans'. But the human body attacks anddestroys tissue from other species. To get around that, one company is trying to alter the pig's geneticcode to prevent pig organs from being attacked. If the company's technicians succeed, it may be moreefficient to produce such pigs by cloning than by current methods.

How would a human clone refer to the donor of its DNA?

'Mom' is not right, because the woman or women who supplied the egg and gave birth to the infantwould more appropriately be called Mother. 'Dad' isn't right, either. A traditional father supplies onlyhalf the DNA in a child. Judith Martin, in her writings under the name of 'Miss Manners';, suggests thephrase, 'Most honored sir or madam'. Why? 'One should always respect one's ancestors,' she says,'regardless of what they did to bring one into the world.'That still leaves some confusion over vocabulary. The editorial director of one dictionary says thatthe noun 'clonee' may sound like a good term, but it's not clear enough. Instead, he prefers 'original'and 'copy'.

What are the other implications of cloning for society?

The gravest concern isn't really cloning itself, but genetic engineering - the deliberate altering ofgenes to create human beings according to certain requirements. Specifically, some experts areconcerned about the creation of a new (and disrespected) social class: 'the clones'. One expert believesthe situation could be comparable to what occurred in the 16th century, when Europeans puzzled overhow to classify the unfamiliar inhabitants of the Americas, and endlessly debated whether or not theywere humans.

The list of questions could go on; people are just beginning to wonder about the future of the worldafter cloning.

起初,这对人们绝对是个震惊。

有消息称科学家已经成功克隆了一只成年哺乳动物,一项长期以来被认为是不可能的成就。这一传闻引发了每个人的想象。

克隆多莉(一只相貌无奇的绵羊)的实验过程,从理论上说也同样适用于克隆人类。

一个克隆人的世界突然间近在咫尺,

科幻小说变成了现实。

此消息宣布之后,为了一个未知世界,一个充满各种不可思议的可能性的未来,各国政府立即起草指导方针。

克林顿总统命令一个全国委员会研究克隆在法律和道德上的含义。

在欧洲,大多数国家都已禁止克隆人类,各国领导此时也开始研究克隆其他物种的道德含义。

就像相对论、原子裂变和第一次太空飞行一样,多莉的出现给科学家、政治家和哲学家们提出了一长串难以解答的难题。

关于克隆的奇怪问题不断涌现。

首先,为什么有人想克隆人类?

专家们考虑得最多的关于克隆人类的情形可以分为两大类:1)父母想要克隆孩子,要么是想为面临死亡威胁的孩子提供移植器官,要么是想代替那个孩子;2)成年人出于各种各样的原因想要克隆自己。

是否可能克隆死去的人?

有位专家说,如果是刚死去不久,也许就可能。

所使用的克隆方法要求将一个卵细胞和一个含有被克隆人的DNA的细胞核相结合。

(DNA是一种含有我们的基因信息的狭长带状分子。)

这就意味着细胞核必须保持完整。

而人死之后,细胞死亡,细胞核就开始分裂。

但是,的确,至少从理论上说克隆死去的人是可能的。

克隆的人会和母本一模一样吗?

相同的基因不会复制出相同的人。任何认识一些双胞胎的人都知道这一点。

事实上,双胞胎相像的程度胜于克隆人,因为他们至少在母体内分享过相同的环境,通常也在同一个家庭里被抚养长大,等等。

父母可能克隆出一个面貌与第一个孩子相似的人,但是所有的证据都表明,这两个人的个性会有很大差异。

一出生就被分开的双胞胎,有时可能有相同的个性特征,但是这样的特征出现在克隆的儿子或女儿身上,却只能令人想起失去的孩子。

即使从生物学的角度看,克隆人也不会和"母本"一模一样。

比如,克隆人的细胞可能会有来自卵子而非被克隆人的能量加工机制。

然而,在母体和克隆体之间存在的身体差异大部分都很小,需要在设备精良的实验室里才能测定。

唯一可能的例外就是生育能力。

成功地实施了克隆多莉的科学家们也不敢肯定多莉是否能生育。

他们会等到多莉到了生育年龄时再确认这一点。

如果父母决定克隆一个孩子以获得器官,那会怎样?

多数专家都认为,如果一个孩子感到自己只是作为一个器官捐赠者来到这个世界,那他的心理可能受到伤害。

但也有为了进行一些非致命器官的移植而生育第二个小孩的父母,对此许多专家也并不反对。

克隆可以将组织适配率从25%提高到将近100%。

如果把被克隆的动物用作器官捐赠体,那我们就不必担心为器官移植而克隆双胞胎了。

例如,猪的器官就和人类的差不多大小。

但是人体会排斥并破坏来自其他物种的组织。

为了克服这一障碍,一家公司正在试图改变猪的基因码,以避免猪的器官受到排斥。

如果该公司的技术人员成功的话,那么用克隆技术来繁殖这样的猪比用现行的方法更为有效。

克隆的人将如何称呼其DNA捐赠者?

称呼"妈妈"不正确,因为提供卵子并生下婴孩的女子才更有资格被称为母亲。

称呼"爸爸"也不对。

传统意义上的父亲只提供孩子身上一半的DNA。

朱迪斯·马丁在用笔名"礼仪小姐"撰写的著作里建议这样称呼:"尊敬的先生/夫人"。

为什么呢?

"不论他们用什么方式将你带到这个世界,"她说,"人总得尊敬自己的祖先。"

这样做还是留下了一些词汇上的难题。

一本词典的主编说,名词"被克隆者"听起来不错,但却不够明晰。

他更愿意用"母本"和"副本"。

克隆对社会还有什么其他含义?

最让人担心的不是克隆本身,而是基因工程──即根据特定的要求故意改变基因来创造人类。

具体地说,有些专家担心会出现一个新的(和不被尊重的)社会阶层,即"克隆阶层"。

有位专家相信,这一情形类似于16世纪时的一种情况,当时的欧洲人对如何对美洲的陌生居民进行归类感到困惑,并无休止地争论他们究竟是不是人类。

问题不胜枚举,而人们只是刚刚开始探询克隆技术出现后的世界的未来。

网友的学习评论(0条):
版权所有©2003-2019 南京通享科技有限公司,保留所有权利。未经书面许可,严禁转载本站内容,违者追究法律责任。 互联网经营ICP证:苏B2-20120186
网站备案:苏ICP备05000269号-1中国工业和信息化部网站备案查询
广播台