UNIT 2 DNA
第二单元 DNA
Lesson 11: Cloning People?
第11课：克隆人？
What if scientists could make clones of human beings?
如果科学家能够克隆人类会怎么样？
Each clone would have the same DNA.
每一个克隆人都有着同样的DNA。
But would they be exactly the same as the original human?
但是他们会和原来的人一模一样吗？
Or would they be different?
或者他们是不同的？
Good question!In some ways,
好问题！从某些方面来说，
clones would be exactly the same.
克隆人会是一模一样的。
They would be the same height and they would have the same hair colour,for example.
例如，他们一样高，有着同样颜色的头发。
But each clone would be a different person.
但是，每一个克隆人都是不一样的。
Why?Because we are more than our DNA.
为什么？因为我们不止受DNA的影响。
Many things change us:
很多事情可以改变我们：
the places we live,the food we eat and the people we know.
我们居住的环境，我们吃的食物和我们认识的人。
Did you know?
你知道吗？
We can only make clones from living DNA.
我们只能用活的DNA来进行克隆。
After a person or animal has died,
一个人或者动物死后，
we cannot clone them.
我们就无法克隆了。
There are two ways to clone people.
克隆人类有两种方法。
We can divide a growing egg in half.
我们可以把一个成长中的胚胎分成两部分。
Then we would have two eggs with the same DNA.
然后我们就有了两个有着一模一样DNA的胚胎。
Or we could clone an adult person,the same way scientists cloned Dolly,the sheep.
或者，我们可以克隆一个成年人，用跟克隆多利一样的方法，就是那只克隆羊。
Would cloning humans be a good or bad thing?
克隆人类是好事，还是坏事？
Why would you clone someone?
为什么要克隆人类呢？
Some people worry about the answer to that question.
有些人担心那个问题的答案。
Other people think human cloning is okay.
有些人觉得克隆人类是可以的。
It may let scientists find new ways to help sick people.
它可以帮助科学家找出帮助病人的新方法。
I think it would be fun to have a twin,
我觉得有一个双胞胎很有意思，
but I don't think I would want to be cloned!
但是我不想被克隆！
Changing DNA ,Can they do that?
改变DNA,他们能这样做吗？
Have you ever seen a pig with a dog's body?
你有没有见过一头长着狗的身体的猪？
Of course not!
当然没有！
Pigs and dogs can't have babies.
猪和狗不能生孩子。
They can't combine their DNA.
它们不能合成它们的DNA。
But now,scientists can.
但是现在，科学家可以。
Scientists can take DNA from one kind of animal
科学家们能够从一种动物中提取DNA，
and put it into another kind of animal.
并把它放进另一种动物体内。
They can design new plants by combining the DNA of other plants.
他们可以通过合成DNA来研究出新的植物。
They can even combine the DNA of a plant and an animal.
他们甚至可以将一种植物和一种动物的DNA进行合成。
What kind of DNA are they wearing?
他们有着什么样的DNA？
Did you know that scientists have changed the DNA of some cotton plants?
你知道科学家们改变了某种棉花的DNA吗？
Many clothes are made of cotton.
许多衣服都是用棉花做的。
Why did scientists change the DNA of cotton plants?
为什么科学家要改变棉花的DNA呢？
Because insects damage many cotton plants.
因为有些昆虫毁坏了棉花。
By changing the DNA,scientists made stronger cotton plants.
通过改变DNA，科学家创造了更健壮的棉花。
What else have scientists designed by changing DNA?
科学家通过改变DNA还研究出了什么？
A new kind of corn.
一种新型玉米。
Ordinary corn has a problem: insects like to eat it!
一般的玉米有一个问题：遭虫咬！
But they don't like to eat the new corn.
但它们不喜欢吃新型的玉米。
A new kind of rice.
一种新型水稻。
Ordinary rice doesn't have Vitamin A.
一般的水稻没有维他命A。
The new rice does,and it's better for you.
新的水稻有，这对你有好处。
Cows that make more milk.
奶牛产更多的牛奶。
What's next?Some scientists are worried.
接着是什么？科学家很担心。
They say we need to know more about DNA before we start changing it.
他们说我们必须在改变它之前，知道更多关于DNA的东西。
We can make plants that are bad for insects.
我们可以造出对昆虫不利的植物。
But what if the plants are bad for humans,too?
但是如果这些植物对人类也有害呢？
Humans are us!People!
人类就是我们！人类！
LET'S DO IT!
做一做
A debate is an argument between two groups.
辩论是两个组之间的争辩。
One group argues for an idea;
一组为一个观点争辩；
the other argues against it.
另一组反对那个观点。
Plan a debate about this topic:
准备一个关于这个话题的辩论：
is it a good idea to change the DNA of the food we eat?
改变我们吃的食物的DNA是一个好主意吗？
Some people say doing this makes our food better.
一些人说这样做会使我们的食物更好.
Others think it is too dangerous.
其他人认为这太危险了。
Search the Internet for information to help your argument!
从网上查找资料帮助你辩论。