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21世紀大學英語讀寫教程第一冊有關克隆的課文介紹
導語：克隆是指生物體通過體細胞進行的無性繁殖，以及由無性繁殖形成的基因型完全相同的后代個體組成的種群。下面YJBYS小編分享一篇關于克隆的英語課文，歡迎閱讀!
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，無性繁殖
surgery
n. 手術;外科
overseas
a. existing somewhere across the sea; foreign (在)海外的;外國的
ad. to, at, or in somewhere across the sea 向海外;在海外
meanwhile
ad. during the same period of time 同時
golf
n. 高爾夫球
far-fetched
a. improbable; not naturally connected 不大可能的;牽強的
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 一模一樣的a.
2. the same 同一的
3. 同卵的
twin
n. 孿生兒之一;[復數] 雙胞胎
a. 孿生的;成雙的
identical twins
[復數] 同卵雙生胎;全等雙生胎
embryologist
n. 胚胎學家
*medication
n. 1. medicine used to cure illness 藥物
2. 藥物治療
*disclose
vt. 1. make known 透露;使公開
2. show by uncovering 使顯露
*clone
vt. 克隆，(無性繁殖)復制
accomplishment
n. a remarkable achievement 成就;造詣
*trigger
vt. (off) start (a chain of events) 觸發;激起
n. 板機;引爆器
unethical
a. morally wrong 不道德的
attempt
n. an effort made to do sth. 企圖，嘗試
vt. make an effort at; try 試圖做
cell
n. 細胞
embryo
n. 胚胎
transform
vt. change completely in form, appearance or nature 徹底改變;將…轉化
specialized, -ised
a. 1. fit for one particular purpose 專門的
2. 專化的;特化的
specialize, -ise
v. 1. 專化，特化
2.(in)專攻;專門研究
muscle
n. 肌肉
implant
vt. (in, into) fix deeply in the body or mind 植入;灌輸
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;雌性動物
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，容納
*genetica. 遺傳的;基因的
blueprint
n. a photographic copy in white or blue paper 藍圖;計劃
exception
n. 例外
organism
n. 1. a living being 生物，有機體
2. a whole made of special parts 有機組織
reprogram
vt. l. 改編…的編碼指令序列
2. 為…重新編程
reproductive
a. concerned with producing young or copying 生殖的;復制的
*forge
vi. (ahead) move steadily and purposely forward 穩步前進
activist
n. a person who takes or supports vigorous action, esp. for a political cause 激進分子，積極分子
tremendous
a. very great in size, amount or degree 巨大的，極大的
alter
v. (cause to) become different 改變，(使)變樣
protein
n. 蛋白質
organ
n. 1. a part of the body with a particular function 器官n.
2. 風琴;管風琴
plentiful
a. existing in large amounts or numbers 充足的，豐富的
donor
n. l.(組織、器官等的)供體，供者
2. a person who gives or presents 贈送人;捐贈者
theoretically
ad. according to theory 理論上
panel
n. 1. a small group of people chosen to do sth. 專門小組
2. 鑲板;嵌板
co-star
vt. 使聯袂主演
fertility
n. 繁殖力;肥沃
specialist
n. expert 專家
*conceive
vt. 1. become pregnant (with a child) 懷(孕);受(孕)
2. think of, imagine 構想;設想
fatal
a. 1. causing death 致命的
2. very dangerous and unfortunate 毀滅性的;不幸的
marrow
n. 髓，骨髓
bonemarrow
n. 骨髓
donation
n. the act of donating or sth. donated 捐贈;捐贈物
offensive
a. causing offense; unpleasant 冒犯的;使人難受的
outlaw
vt. declare unlawful 宣布…為非法
n. criminal 歹徒;逃犯
ethicist
n. 倫理學家
meantime
n. the time between two events 其間，其時
impose
vt. (on, upon) 1. force the acceptance of 把…強加于
2. establish (an additional payment) officially 征(稅)
ban
n. (on) an order to forbid sth. 禁令;禁止
vt. forbid by law 禁止;取締
federal
a. l. [F-](美國)聯邦政府的
2. 聯盟的;聯邦的
*ethics
n. 倫理學;道德學
flunk
vt. fail (an examination or course) 通不過(考試等)
off-key
a. 走調的，不和諧的
opponent
n. a person who acts against sb. or sth. or who takes the opposite side 反對者;對手;敵手
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 換句話說
on one's way to
moving towards 接近，將要
to much surprise
令人大為驚異的是
in theory
理論上
give birth to
produce 產(仔);生(孩子)
jump in
join in with vigor or eagerness (踴躍或熱切地)加入
up in arms
angry (about sth.) and protesting strongly 極力反對
draw the line at
refuse to do or accept 拒絕做;拒絕接受
set up
found or establish 設立，建立
in the meantime
in the period of time between two events 在此期間，與此同時
start out
begin 開始
object to
be against 反對
Proper Names
Chana Freiman Stiefel
查納·弗賴曼·施蒂費爾(人名)
Bill Clinton
比爾·克林頓(1946 —，美國第四十二任總統)
Boris Yeltsin
鮑里斯·葉利欽(1931 —，俄羅斯聯邦第一任總統)
Chelsea
切爾西(女子名)
Scotland
蘇格蘭(英國的一部分，在大不列顛島北部)
Dolly
多利(世界上第一只克隆羊)
lan Wilmut
伊恩·威爾莫特(人名)
Oregon
俄勒岡州(美國州名)
Frankenstein
弗蘭肯斯坦(英國女作家 Mary W.Shelley 所著同名小說中的主角，一個創造怪物而自己被它毀滅的`醫學研究者)
Denmark
丹麥(北歐國家)
Danish
丹麥的
Brad Pitt
布拉德·皮特(美國影星)
Mark Hanson
馬克·漢森(人名)
Briarcliff Manor
布里爾克利夫·馬納(地名)
Cleveland Amory
克利夫蘭·艾默里(人名)
the Fund for Animals
動物基金會
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