Humans have DNA. Pigs have DNA. Even bacteria and some viruses have DNA too. 人类有DNA。猪有DNA。甚至细菌和一些病毒都有DNA。

The genetic instructions encoded in DNA inform how our bodies develop, grow, function. 编码在DNA中的遗传指令，告诉我们的身体如何发育，成长和发挥机能。

And in many cases, that same information can trigger disease. 而且在很多情况下，同样的信息还能引发疾病。

Your genetic information is strung into a long and twisted molecule, 你的遗传信息串成了一段长而扭曲的分子，

the DNA double helix, that has over three billion letters, beginning to end. 即DNA双螺旋结构，它有着超过三十亿个碱基，从开始到结束。

But the lines that carry meaningful information are usually very short -- a few dozen to several thousand letters long. 但是携带有意义的信息的那几行，通常却很短--只有几十到几千个字母那么长。

So when we're looking to answer a question based on DNA, we actually don't need to read all those three billion letters, typically. 所以当我们在寻找基于DNA问题的答案时，我们实际上并不需要去读完所有的那三十亿个字。

That would be like getting hungry at night and having to flip through the whole phone book from cover to cover, 这会像在晚上觉得很饿，然后不得不翻阅整个电话簿，从头到尾，

pausing at every line, just to find the nearest pizza joint. 一行不落，只是为了找到最近的披萨店。

Luckily, three decades ago, humans started to invent tools that can find any specific line of genetic information. 幸运的是，三十年前，人类开始发明工具，使我们能找到任何一种特定的遗传信息。

These DNA machines are wonderful. They can find any line in DNA. 这些DNA检测器非常棒。它们能查找出DNA中任何一行的信息。

But once they find it, that DNA is still tiny, and surrounded by so much other DNA, 但虽然它们找到了它，DNA仍然很小，而且周围那么多其他的DNA，

that what these machines then do is copy the target gene, and one copy piles on top of another, 那么这些机器接下来做的便是复制目标基因，复制一份又一份，

millions and millions and millions of copies, until that gene stands out against the rest; 成千上万次，直到那个与众不同的基因出现；

until we can visualize it, interpret it, read it, understand it, until we can answer: Does my pig have the flu? 直到我们能看见它，解释它，读懂它，理解它，直到我们能回答：我的猪得了流感吗？

Or other questions buried in our own DNA: Am I at risk of cancer? 或者其他埋藏在我们自己DNA中的问题：我有患癌症的风险吗？

Am I of Irish descent? Is that child my son? 我有爱尔兰血统吗? 那孩子是我亲生的吗？