21世纪大学英语读写教程第一册有关克隆的课文介绍
导语：克隆是指生物体通过体细胞进行的无性繁殖，以及由无性繁殖形成的基因型完全相同的后代个体组成的种群。下面YJBYS小编分享一篇关于克隆的英语课文，欢迎阅读!
Cloning:
good Science or Baaaad Jdea
Chana Freimans Stiefel
Just before President Clinton heads to the hospital for knee surgery, he asks another Bill Clinton to meet Russian President Boris Yeltsin at an overseas meeting. Meanwhile, a third Bill Clinton is out playing golf, while a fourth is helping daughter Chelsea with a science project.
Sound far-fetched? That day may come. Scientists in Scotland recently announced that, for the first time, they have cloned an exact copy of an adult sheep. The cloned baby lamb, named Dolly, has the exact same 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 lan Wilmut, the lead scientist, is to develop a way to raise identical sheep that produce medications for humans.
A week after Wilmut's announcement, scientists in Oregon disclosed that they had used a different technique to clone monkeys, close cousins of humans. Faster than you can say "Frankenstein," these accomplishments triggered a worldwide debate: Should scientists be allowed to clone animals? Will humans be next? Is cloning unethical and dangerous—or is it a valuable research tool?
All attempts at cloning were largely unsuccessful until 1984. That's when a scientist in Denmark separated cells from a sheep's embryo. An embryo is an early stage of development in which cells are busy dividing and "transforming" into specialized cells like skin, eye, or muscle cells.
Unlike a skin cell, an embryo is on its way to becoming a complete living thing. The Danish scientist combined an embryo cell with an egg cell from another sheep. He implanted the fused cell - then a newly growing embryo - into a grown female sheep. To much surprise, the embryo grew into a baby lamb. Since then, other scientists have used embryos to clone cattle, pigs, goats, rabbits - and, now, even monkeys.
So what makes Wilmut's sheep unique? Instead of using early-stage embryo cells, Wilmut used cells from the udder of an adult sheep. In theory, that's like using one of your skin cells to clone a new you!
Wilmut knew that each cell of the body contains a full set of genetic instructions—a blueprint to grow a complete individual. (The only exceptions are egg and sperm cells, each of which contains half the genes to grow a new individual.) Once cells have specialized, on their way to becoming skin or eye or udder cells, most of the genetic instructions to make a full being are turned off. Until now, scientists believed that specialized cells could not be used to form a complete organism.
Wilmut proved them wrong. He found a way to "reprogram" an udder cell and make it grow into a new cloned lamb. An amazing fact: Dolly has no biological father.
Wilmut's success didn't come easily. He has been studying reproductive science for more than two decades. Last year, he used embryos to successfully clone two sheep. Then he forged ahead to clone an adult sheep. But, of 277 udder cells he fused with egg cells, only 30 began to develop into embryos. He implanted 29 of those into female sheep. Only one adult gave birth to a lamb.
Other scientists have jumped in to repeat Wilmut's experiment with other animals, including cows. And that's what has scientists, animal-rights activists, politicians—even President Clinton — up in arms. How far, they wonder, will cloning go?
Wilmut maintains that cloning animals has tremendous potential for helping people. Cloned sheep, he says, 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.
Why not clone humans as organ donors? Theoretically, Wilmut says, there is no reason his techniques couldn't someday be used to clone people. Think about the possibilities: a whole team of Michael Jordans, a scientific panel of Albert Einsteins, a movie starring and co-starring Brad Pitt.
On a more serious note, some fertility specialists argue 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, creating a twin who is an exact match for bone-marrow donation.
But even lan Wilmut draws the line at cloning humans. "All of us would find that offensive," he says. Several countries, including Britain, Denmark, Germany, and Australia, have outlawed all scientific work on cloning humans. The U.S. has no such law, but President Clinton has set up a panel of scientists and ethicists to study the issue. In the meantime, Clinton has imposed a ban on using Federal money to clone humans.
Humans are more than the sum of their genes, argues Mark Hanson, an ethicist at an ethics research institute in Briarcliff Manor, New York. Though they look exactly the same, clones are not necessarily carbon copies. The younger twin might grow up with different influences—say, unusual friends or special teachers. A cloned Albert Einstein might flunk physics. A cloned Madonna might sing off-key.
Say you were cloned. Would your twin live a shorter life because he or she started out with teenage genes? Scientists aren't sure. And how could you prevent someone from taking a sample of your hair and making a clone of you? Again, no solutions.
Some opponents of cloning also object to the use of animals as research tools. "Next, they'll be cloning minks and foxes to make more fur coats," says Cleveland Amory, president and founder of the Fund for Animals, an animal rights group.
What do you think? Should scientists be allowed to clone animals? How about humans?
New Words
cloning
n. 克隆，无性繁殖
surgery
n. 手术;外科
overseas
a. existing somewhere across the sea; foreign (在)海外的;外国的
ad. to, at, or in somewhere across the sea 向海外;在海外
meanwhile
ad. during the same period of time 同时
golf
n. 高尔夫球
far-fetched
a. improbable; not naturally connected 不大可能的.;牵强的
lamb
n. a young sheep; the meat of a young sheep 羔羊;羔羊肉
gene
n. 基因
identical
a. 1. (with, to) exactly alike 一模一样的a.
2. the same 同一的
3. 同卵的
twin
n. 孪生儿之一;[复数] 双胞胎
a. 孪生的;成双的
identical twins
[复数] 同卵双生胎;全等双生胎
embryologist
n. 胚胎学家
*medication
n. 1. medicine used to cure illness 药物
2. 药物治疗
*disclose
vt. 1. make known 透露;使公开
2. show by uncovering 使显露
*clone
vt. 克隆，(无性繁殖)复制
accomplishment
n. a remarkable achievement 成就;造诣
*trigger
vt. (off) start (a chain of events) 触发;激起
n. 板机;引爆器
unethical
a. morally wrong 不道德的
attempt
n. an effort made to do sth. 企图，尝试
vt. make an effort at; try 试图做
cell
n. 细胞
embryo
n. 胚胎
transform
vt. change completely in form, appearance or nature 彻底改变;将…转化
specialized, -ised
a. 1. fit for one particular purpose 专门的
2. 专化的;特化的
specialize, -ise
v. 1. 专化，特化
2.(in)专攻;专门研究
muscle
n. 肌肉
implant
vt. (in, into) fix deeply in the body or mind 植入;灌输
fuse
vt. 1. cause to melt in great heat 熔化
2. cause to join by melting 熔合
female
a. 女性的;雌的
n. 女子;雌性动物
rabbit
n. 野兔;兔肉
udder
n. (母牛、母山羊的)乳房;乳腺
contain
vt. hold, have within itself 包含，容纳
*genetica. 遗传的;基因的
blueprint
n. a photographic copy in white or blue paper 蓝图;计划
exception
n. 例外
organism
n. 1. a living being 生物，有机体
2. a whole made of special parts 有机组织
reprogram
vt. l. 改编…的编码指令序列
2. 为…重新编程
reproductive
a. concerned with producing young or copying 生殖的;复制的
*forge
vi. (ahead) move steadily and purposely forward 稳步前进
activist
n. a person who takes or supports vigorous action, esp. for a political cause 激进分子，积极分子
tremendous
a. very great in size, amount or degree 巨大的，极大的
alter
v. (cause to) become different 改变，(使)变样
protein
n. 蛋白质
organ
n. 1. a part of the body with a particular function 器官n.
2. 风琴;管风琴
plentiful
a. existing in large amounts or numbers 充足的，丰富的
donor
n. l.(组织、器官等的)供体，供者
2. a person who gives or presents 赠送人;捐赠者
theoretically
ad. according to theory 理论上
panel
n. 1. a small group of people chosen to do sth. 专门小组
2. 镶板;嵌板
co-star
vt. 使联袂主演
fertility
n. 繁殖力;肥沃
specialist
n. expert 专家
*conceive
vt. 1. become pregnant (with a child) 怀(孕);受(孕)
2. think of, imagine 构想;设想
fatal
a. 1. causing death 致命的
2. very dangerous and unfortunate 毁灭性的;不幸的
marrow
n. 髓，骨髓
bonemarrow
n. 骨髓
donation
n. the act of donating or sth. donated 捐赠;捐赠物
offensive
a. causing offense; unpleasant 冒犯的;使人难受的
outlaw
vt. declare unlawful 宣布…为非法
n. criminal 歹徒;逃犯
ethicist
n. 伦理学家
meantime
n. the time between two events 其间，其时
impose
vt. (on, upon) 1. force the acceptance of 把…强加于
2. establish (an additional payment) officially 征(税)
ban
n. (on) an order to forbid sth. 禁令;禁止
vt. forbid by law 禁止;取缔
federal
a. l. [F-](美国)联邦政府的
2. 联盟的;联邦的
*ethics
n. 伦理学;道德学
flunk
vt. fail (an examination or course) 通不过(考试等)
off-key
a. 走调的，不和谐的
opponent
n. a person who acts against sb. or sth. or who takes the opposite side 反对者;对手;敌手
mink
n. 水貂;水貂毛皮
Phrases and Expressions
for the first time
第一次，破天荒
in other words
expressing the same meaning in another way 换句话说
on one's way to
moving towards 接近，将要
to much surprise
令人大为惊异的是
in theory
理论上
give birth to
produce 产(仔);生(孩子)
jump in
join in with vigor or eagerness (踊跃或热切地)加入
up in arms
angry (about sth.) and protesting strongly 极力反对
draw the line at
refuse to do or accept 拒绝做;拒绝接受
set up
found or establish 设立，建立
in the meantime
in the period of time between two events 在此期间，与此同时
start out
begin 开始
object to
be against 反对
Proper Names
Chana Freiman Stiefel
查纳·弗赖曼·施蒂费尔(人名)
Bill Clinton
比尔·克林顿(1946 —，美国第四十二任总统)
Boris Yeltsin
鲍里斯·叶利钦(1931 —，俄罗斯联邦第一任总统)
Chelsea
切尔西(女子名)
Scotland
苏格兰(英国的一部分，在大不列颠岛北部)
Dolly
多利(世界上第一只克隆羊)
lan Wilmut
伊恩·威尔莫特(人名)
Oregon
俄勒冈州(美国州名)
Frankenstein
弗兰肯斯坦(英国女作家 Mary W.Shelley 所著同名小说中的主角，一个创造怪物而自己被它毁灭的医学研究者)
Denmark
丹麦(北欧国家)
Danish
丹麦的
Brad Pitt
布拉德·皮特(美国影星)
Mark Hanson
马克·汉森(人名)
Briarcliff Manor
布里尔克利夫·马纳(地名)
Cleveland Amory
克利夫兰·艾默里(人名)
the Fund for Animals
动物基金会
【21世纪大学英语读写教程第一册有关克隆的课文介绍】相关文章：
泰语数字读写教程05-27
英语如何听说读写11-20
新概念英语第一册课文及翻译11-02
javascript克隆对象深度介绍11-17
教你的英语如何听说读写11-21
英语听说读写经验分享08-25
英语听说读写的教学分析11-20
怎么提高考博英语的听说读写09-30