新视野大学英语读写教程听力 第三册 te-unit08-a

英语听力 2019-08-13 06:10:54 112
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[00:00.00],就把hxen.com复制到QQ个人资料中!Legal and Moral Implications of Cloning
[00:04.43]1  At first it was just plain surprising.
[00:09.25]Word last week that a scientist named Ian Wilmut
[00:14.29]had succeeded in cloning an adult mammal
[00:17.64]— an achievement long thought impossible
[00:20.88]— caught the imagination of everyone.
[00:23.90]The laboratory process that produced Dolly,
[00:28.37]an unremarkable-looking sheep,
[00:31.21]theoretically would for humans as well.
[00:35.21]A world with human clones was suddenly within reach.
[00:41.08]It was science fiction coming to life.
[00:44.60]2  In the wake of Wilmut\'s announcement,
[00:49.64]governments hurried to draft guidelines for the unknown,
[00:54.04]a future filled with incredible possibilities.
[00:58.36]President Clinton ordered a national commission to study
[01:03.00]the legal and moral implications of cloning.
[01:06.67]Leaders in Europe,
[01:09.52]where most nations already prohibit human cloning,
[01:13.30]began examining the moral implications of cloning other species.
[01:18.88]3  Like the Theory of Relativity, the splitting of the atom,
[01:24.42]and the first space flight,
[01:26.29]Dolly\'s appearance has generated a long list of difficult puzzles
[01:31.58]for scientists, politicians, and philosophers.
[01:35.94]And we wild questions on the topic of cloning continue to mount.
[01:42.10]4  Why would anyone want to clone a human being in the first place?
[01:48.83]5  The human cloning situations that experts consider
[01:54.23]most frequently fall into two broad categories:
[01:58.91]1) parents who want to clone a child,
[02:03.01]either to provide transplants for a dying child or to replace that child,
[02:09.10]and 2) adults who for a variety of reasons might want to clone themselves.
[02:17.09]6  Will it be possible to clone the dead?
[02:21.84]7  Perhaps, if the body is fresh, says one experts.
[02:26.99]The cloning method used by Wilmut\'s lab requires combining an egg cell
[02:33.25]with the nucleus of a cell containing the DNA of the person to be cloned.
[02:40.24](DNA is a very long,
[02:44.77]ribbon-like molecule that contains our genetic information.)
[02:50.17]And that means that the nucleus must be intact.
[02:55.93]Cells die and the cell nucleus begins to break apart after death.
[03:02.95]But, yes, in theory at least it might be possible.
[03:07.99]8  Would a cloned human be identical to the original?
[03:13.97]9  Identical genes don\'t produce identical people,
[03:19.76]as anyone who knows a set of identical twins can tell you.
[03:24.84]In fact, twins are more alike than clones would be,
[03:30.31]since they have at least shared the same environment within the mother,
[03:35.35]are usually raised in the same family, and so forth.
[03:39.89]parents could clone a second child
[03:43.49]who resembled their first in appearance,
[03:46.66]but all the evidence suggests
[03:49.28]the two would have very different personalities.
[03:53.06]Twins separated at birth do sometimes share personality characteristics,
[04:01.74]but such characteristics in a cloned son or daughter
[04:06.64]would only be reminders of the child who was lost.
[04:11.32]10  Even in terms of biology,
[04:14.95]a clone would not be identical to the "master copy".
[04:20.03]The clone\'s cells, for example,
[04:24.06]would have energy-processing machinery that came from the egg,
[04:29.14]not from the person who was cloned.
[04:31.91]But most of the physical differences
[04:35.44]between originals and copies are so minor that detection
[04:40.51]of them would require a sophisticated laboratory.
[04:44.69]The one possible exception is bearing children.
[04:48.12]Wilmut and his coworkers are not sure that Dolly will be able to have lambs.
[04:56.22]They will try to find out once she\'s old enough to breed.
[05:02.27]11  What if parents decided to clone a child in order to harvest organs?
[05:11.88]12  Most experts agree that it would be psychologically harmful
[05:17.46]if a child sensed he had been brought into the world

[05:20.70]simply as an organ donor.
[05:23.76]But some parents already produce second children
[05:28.40]with nonfatal transplants in mind,
[05:31.64]and many experts do not oppose this.
[05:34.88]Cloning would increase the chances for a tissue match
[05:39.81]from 25 percent to nearly 100 percent.
[05:44.67]13  If cloned animals could be used as organ donors,
[05:51.12]we wouldn\'t have to worry about cloning twins for transplants.
[05:55.91]Pigs, for example, have organs similar in size to humans\'.
[06:02.39]But the human body attacks and destroys tissue from other species.
[06:09.41]To get around that, one company is trying to alterthe pig\'s genetic code
[06:16.46]to prevent pig organs from behind attacked.
[06:20.64]If the company\'s technicians succeed.
[06:24.35]it may be more efficient to produce such pigs by cloning than by current methods.
[06:31.83]14  How would a human clone refer to the donor of its DNA?
[06:38.82]15  "Mom" is not right,
[06:42.71]because the woman or women who supplied the egg
[06:46.77]and gave birth to the infant would more appropriately be called Mother.
[06:52.71]"Dad" isn\'t right, either.
[06:55.88]A traditional father supplies only half the DNA in a child.
[07:01.97]Judith Martin, in her writings under the name of "Miss Manners",
[07:07.62]suggests the phrase,"Most honored sir or madam". Why?
[07:14.10]"One should always respect one\'s ancestors," she says,
[07:19.03]"regardless of what they did to bring one into the world."
[07:23.31]16  That still leaves some confusion over vocabulary.
[07:22.31]The editorial director of one dictionary says that the noun
[07:27.82]"clonee" may sound like a good term,
[07:31.10]but it\'s not clear enough.Instead, he prefers "original" and "copy".
[07:39.16]17  What are the other implications of cloning for society?
[07:45.53]18  The gravest concern isn\'t really cloning itself,
[07:50.57]but genetic engineering — the deliberate altering of genes
[07:55.97]to create human beings according to certain requirements.
[08:01.16]Specifically, some experts are concerned about the creation of a new
[08:07.60](and disrespected) social class: "the clones".
[08:13.18]One expert believes the situation could be comparable
[08:17.43]to what occurred in the 16th century,
[08:20.81]when Europeans puzzled over how to classify
[08:25.06]the unfamiliar inhabitants of the Americas,
[08:29.31]and endlessly debated whether or not they were humans.
[08:34.17]19  The list of questions could go on;
[08:37.95]people are just beginning to wonder
[08:40.97]about the future of the world after cloning.
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