时差N小时 大自然中的基因交易(下)（在线收听）

In order to add some variety to their genetic makeup, bacteria swap genes 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 DNA called plasmids. A bacterium 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 bacterial “insider trading.”

这就是细菌“内部交易”的神奇和可怕之处。