时差N小时 大自然中的基因交易(下)

In order to add some variety to their genetic¹ makeup², bacteria swap³ genes⁴ with other bacteria.

为丰富基因结构的多样性，细菌与细菌会进行基因交易。

They trade tiny loops of DNA⁵ called plasmids. A bacterium⁶ makes a plasmid by copying part of its DNA.

它们交换的微小的DNA链被称为质粒。 一个细菌体通过复制自身部分的DNA产生质粒。

Then it trades its plasmid for one from another bacterium–in fact, just about any other bacterium!

然后，细菌会和其他细菌交换质粒——实际上，是任意的一个细菌！

That’s right–the trading partners don’t need to be the same kind of bacteria, or even related kinds!

没错，交易双方不必为同一类细菌，甚至不必为相似种类的细菌！

Just about any two bacteria can swap plasmids.

只要两个细菌能够交换质粒。

That’s great for bacteria, but not always so great for everyone else.

虽然这种交易对细菌有益，但对其他物种则不然。

It can be a big problem if a traded plasmid carries genes for drug resistance.

如果细菌交易的质粒带有抗药性基因，那就是一场大灾难。

If just one type of bacteria–even a harmless type–develops resistance to a drug, it can pass on that resistance to other types of bacteria that aren’t so harmless!

只要一种细菌——哪怕是无害的种类——生成了抗药性，它可以把抗药性基因传递给有害细菌！

That’s the magic, and the menace, of bacterial⁷ “insider trading.”

这就是细菌“内部交易”的神奇和可怕之处。

1 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

2 makeup   

n.组织；性格；化装品

参考例句：

• Those who failed the exam take a makeup exam.这次考试不及格的人必须参加补考。
• Do you think her beauty could makeup for her stupidity?你认为她的美丽能弥补她的愚蠢吗？

3 swap   

n.交换；vt.交换，用...作交易

参考例句：

• I will swap you my bicycle for your radio.我想拿我的自行车换你的收音机。
• This comic was a swap that I got from Nick.这本漫画书是我从尼克那里换来的。

4 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

5 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

6 bacterium   

n.(pl.)bacteria 细菌

参考例句：

• The bacterium possibly goes in the human body by the mouth.细菌可能通过口进入人体。
• A bacterium is identified as the cause for his duodenal ulcer.一种细菌被断定为造成他十二指肠溃疡的根源。

7 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。