Gene therapy and gene-based drugs are two ways we could benefit from our growing mastery of genetic science．But there will be others as well．Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years．
While it's true that just about every eell in the body has the instructions to make a complete human’ most of those instructions are inactivated，and with good reason：the last thing you want is for your brain cells to start churning out stomach acid or your nose to turn into a kidney．①The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy,when so-called stem cells haven’t begun to specialize．
Yet this untapped potential could be a terrific boon to medicine．Most diseases involve the death of healthv cells—brain cells in Alzheimer’s，cardiac cells in heart disease，pancreatic cells in diabetes，to name a few．If doctors could isolate stem cells，then direct their growth，they might be able to furnish patients with healthy replacement tissue．
It was incredibly difficult，but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural，gut，muscle and bone cells．The process still can’t be controlled，and may have unforeseen limitations．But if efforts to understand and master stem-cell develoDment prove successful，doctors will have a therapeutic tool of incredible power．
The same applies to clonin9，which is really just the other side of the coin．True cloning'as first shown with Dolly the sheep two years a90，involves taking fl developed cell and reactivating the genome within。resetting its developmental instructions to a pristine state．Once that happens，the rejuvenated cell can develop into a full—fledged animal，genetically identical to its parent．
For agriculture，in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value，biological carbon copies could become routine within a few years．⑦This past year scientists have done for mice and cows what Ian Witmut did for Dolly，and other creatures are bound to join the cloned menagerie in the coming year．
Human clonin9，on the other hand，may be technically feasible but legally and emotionally more difficult．Still，one day it will happen．The ability to reset body cells to a pristine，undeveloped state could give doctors exactly the same advantages they would get from stem cells：the potential to make healthy body tissues of all sorts。and thus to cure disease．④That could prove to be a true“miracle cure”． [447 words]
1．The author believes that______．
A．there will inevitably be human cloning in the coming year
B．the potential to make healthy body tissues is undoubtedly a blessing to human beings，
C．it is illegal to clone any kind of creatures in the world
D．it is legal to clone any kind of creatures in the world except human
2．Which of the following statements is NOT TRUE according to this passage?
A．Nearly every cell in the human brain has the instructions to make a complete human.
B．It is impossible for a eell in your nose to turn into a kidney．
C．It is possible to turn OUt healthy replacement tissues with isolated stem cells．
D．There will certainly appear some new kind of cloned animal in the near future．
3．According to this passage，______isn’t a step involved in true clonin9．
A．selecting a stem cell
B．taking a developed cell
C．reactivating the genome within the developed cell
D．resetting the developmental instructions in the cell to its original state
4．In the author’s opinion，the potential of a cell to turn into any body parts is ______．
A．negligible
B．inactivated
C．worth tapping
D．beyond question
5．The proper title for this passage should be______．
A．Tomorrow’s Tissue Factory
B．A Terrific Boon to Medicine
C．Human Cloning
D．Genetic Research [NextPage]
难句透析
①While it’S true[that just about every cell in the body has the instructions to make a complete human-]，most of those instructions are inactivated，and with good reason：the last thing you want is for your brain cells to start chur- ning out stomach acid or your nose tO turn into a kidney．
【结构】本句中的“the last thing you want”表达否定意思。
【释义】几乎身体中的每一个细胞都隐含有发育成一个完整人体的密码指令。虽说真是如此，但其中绝大多数指令没有被激活。理由很充分：你绝对不希望你的脑细胞分泌出胃酸，也不希望鼻子发育成肾。
②For agriculture，Ein which purely physical characteristics like milk production in a cow or low fat in a hog have real market value-]，biological carbon copies could become routine within a few years．
【结构】在本句中，方括号所标示的由“in which”引导的非限制性定语从句修饰“agriculture”。
【释义】在农业方面，诸如奶牛的产奶量和肉猪的低脂肪这些纯粹的自然属性有真正的商业价值。对于农业来说，用不了几年，生物克隆会变成司空见惯的事。
③The ability to reset body cells tO a pristine，undeveloped state could give doctors exactly the same advantages[they would get from stem ceils-]：the potential to make healthy body tissues of all sorts，and thus to cure disease．
【结构】在本句中，方括号所标示的部分是定语从句，修饰“advantages”。
【释义】把肌体细胞重新调节到初始的、未发育的状态，这种能力可以给医生带来他们从干细胞中获得的同样好处：有可能培育出各种各样的健康的人体组织，并用来治病。
全文翻译
基因疗法以及基于基因技术的药品是我们对基因科学不断增长的了解所带来的两项好处。当然其他的好处也会相继出现。目前就有这样一种相当了不起的处于基因研究的前沿水平的治疗技术，并且有望在未来的几年中进入医药主流。
几乎身体中的每一个细胞都隐含有发育成一个完整人体的密码指令。虽说真是如此，但其中绝大多数指令没有被激活。理由很充分：你绝对不希望你的脑细胞分泌出胃酸，也不希望鼻子发育成肾。细胞具有转化成任何身体组织并最终形成整个人体的能力的唯一时段就是怀孕的早期，那个时候被称为干细胞的细胞还没有开始特殊分类。
不过，这种未被开发的潜能对医学可能产生极大的好处。多种疾病都涉及健康细胞的死亡，随便举几个例子——早老性痴呆病的脑细胞，心脏病中的心肌细胞，糖尿病中的胰脏细胞等等。如果医生能把干细胞分离出来，引导其发育，就可能为病人提供可供替换用的健康的肌体组织。
这是相当困难的，但是去年秋天，威斯康辛大学的科学家们设法分离出了干细胞，并使其发育成了神经细胞、肠细胞、肌肉细胞和骨细胞。这个过程仍不受控制，而且看起来或许存在不可预见的限制。但是如果对干细胞生长的了解和掌握能取得成功的话，医生们将获得一个具有不可思议的治疗力量的工具。
同样的原理对克隆技术也同样适用，因为克隆和干细胞研究就像是一枚硬币的正反面一样。真正的克隆技术，就如同两年前在克隆羊多莉身上实现的那样，需要取出一个成熟的细胞并重新激活其内部的基因组，同时将其发育指令重调到初始状态。当这一切都实现了之后，这个被激活的细胞将生长成为一只和其母体完全一样的完整的动物。
在农业方面，诸如奶牛的产奶量和肉猪的低脂肪这些纯粹的自然属性有真正的商业价值。对于农业来说，用不了几年，生物克隆会变成司空见惯的事。在过去的这一年中，科学家们在老鼠和奶牛的身上重复了伊安·维尔莫在多莉身上做的实验，相信在未来几年中其它的生物也将加入克隆动物的生物圈。
从另一方面来说，对人类的克隆从技术上来说有可行性，不过从法律和感情的角度来说难以接受。但有朝一日终会实现。把肌体细胞重新调节到初始的、未发育的状态，这种能力可以给医生带来他们从干细胞中获得的同样好处：有可能培育出各种各样的健康的人体组织，并用来治病。它将成为真正的“神奇治疗”。
超纲词汇
Alzheimer’S disease n．阿耳茨海默氏病，早老性痴呆病
carbon copy复写本，副本
cardiac adj．心脏的
churn out艰苦地做出
diabetes n．糖尿病，多尿症
full—fledged 羽毛生齐的，有充分资格的，发育完全的
gut n．内脏，肠子
hog n．肥(公)猪
menagerie n．动物园，动物展览
mice n．(pl．)老鼠
neural adj．神经系统的，神经中枢的，背的
pancreatic adj．胰腺的
pregnancy n．怀孕
pristine adj．质朴的
rejuvenate vt．／vi．复原，恢复精神
therapeutic 治疗的，治疗学的
unforeseen adj．无法预料的
untapped adj．塞子未开的，未使用的
参考答案：1．B 2．B 3．A 4．C 5．A
