and put off aging?  延缓衰老呢？

　　This is a dream of the ages.  这是很久以来的梦想了

　　But scientists have for a long time  不过科学家以前一直认为

　　thought this just was never going to be possible.  这大概根本永远不可能

　　They thought you just wear out, there's nothing you can do about it --  他们认为每个人就是慢慢被消耗这个事实没办法改变

　　kind of like an old shoe.  就像被磨损的旧鞋子

　　But if you look in nature,  不过转而观察大自然的话

　　you see that different kinds of animals  我们发现不同种的动物

　　can have really different lifespans.  寿命差异可以非常之大

　　Now these animals are different from one another,  这些动物彼此不一样

　　because they have different genes.  是因为它们有不同的基因

　　So that suggests  这就启发我们

　　that somewhere in these genes, somewhere in the DNA,  在这些基因里的某个地方，在DNA里面

　　are genes for aging,  有控制衰老的基因

　　genes that allow them to have different lifespans.  让动物们有不同的寿命期

　　So if there are genes like that,  所以有这样的基因

　　then you can imagine that,  我们就能想像到

　　if you could change one of the genes in an experiment,  如果我们通过实验改变一个基因

　　an aging gene,  那个衰老基因

　　maybe you could slow down aging and extend lifespan.  说不定就可以延缓衰老，延长寿命

　　And if you could do that, then you could find the genes for aging.  如果这样做了，就可以找到那些衰老基因

　　And if they exist and you can find them,  如果这些衰老基因真的存在并且能找到

　　then maybe one could eventually do something about it.  那也许有人就能对它做点什么

　　So we've set out to look for genes that control aging.  所以我们就开始寻找那些控制衰老的基因

　　And we didn't study any of these animals.  不过我们没有研究刚才那些动物

　　Instead, we studied a little, tiny, round worm called C. elegans,  而是研究一种小小圆圆的蠕虫，叫做秀丽隐杆线虫

　　which is just about the size of a comma in a sentence.  大小刚好和句子里面逗号的大小差不多

　　And we were really optimistic that we could find something  我们很有信心能找到相关的基因

　　because there had been a report of a long-lived mutant.  因为曾经有种长寿变异的个体记录在案

　　So we started to change genes at random,  所以我们就随机改变线虫的基因

　　looking for long-lived animals.  寻找长寿的那些

　　And we were very lucky to find  结果我们很幸运地发现

　　that mutations that damage one single gene called daf-2  损坏单个基因daf-2的这种变异

　　doubled the lifespan of the little worm.  能让这种小虫的寿命翻倍

　　So you can see in black, after a month --  所以能看到这条黑色曲线，一个月以后--

　　they're very short-lived; that's why we like to study them  这些线虫的寿命很短，这就是为什么我们用它们来做

　　for studies of aging --  寿命的研究--

　　in black, after a month, the normal worms are all dead.  黑色曲线表示一个月以后，正常线虫都死亡了

　　But at that time,  但是同时

　　most of the mutant worms are still alive.  大部分变异线虫还活着

　　And it isn't until twice as long  直到又过了同样长的时间

　　that they're all dead.  它们才死亡

　　And now I want to show what they actually look like in this movie here.  现在我来用视频演示线虫真正是什么样子

　　So the first thing you're going to see  首先这里看到的

　　is the normal worm  是正常的线虫

　　when it's about college student age -- a young adult.  大概在我们大学生的年龄--青年人的年龄

　　It's quite a cute little fellow.  很可爱的小家伙

　　And next you're going to see the long-lived mutant when it's young.  下面你将看到年轻的长寿变异体

　　So this animal is going to live twice as long.  它会活到正常线虫两倍的年龄

　　Is it miserable? It doesn't seem to be.  很可怜吧？其实不是

　　It's active. You can't tell the difference really.  它相当活跃，和正常线虫几乎看不出区别

　　And they can be completely fertile --  而且它们也有繁殖能力--

　　have the same number of progeny as the normal worms do.  后代的数目可以和正常线虫的一样多

　　Now get out your handkerchiefs here.  现在准备拿出手绢来擦眼泪吧

　　You're going to see, in just two weeks,  你会看到，就在仅仅两周之后

　　the normal worms are old.  正常的线虫就老了

　　You can see the little head moving down at the bottom there.  可以看见它的头在屏幕下面，在动

　　But everything else is just lying there.  但是其它部位就只是躺在那儿不动

　　The animal's clearly in the nursing home.  它显然已经在老人院了

　　And if you look at the tissues of the animal, they're starting to deteriorate.  再看它的身体组织，能看到已经老化了

　　You know, even if you've never seen one of these little C. elegans --  你看，就算从来没见过秀丽隐杆线虫--

　　which probably most of you haven't seen one --  多数人应该是没见过--

　　you can tell they're old -- isn't that interesting?  你就知道它们老了--这不是很有意思吗？

　　So there's something about aging that's kind of universal.  衰老这件事是有普世性的

　　And now here is the daf-2 mutant.  现在这个是daf-2变异体

　　One gene is changed out of 20,000, and look at it. 20000个基因里只改变了一个，看

　　It's the same age, but it's not in the nursing home;  年龄是一样的，但是它不在养老院里

　　it's going skiing.  它看起来在滑雪

　　This is what's really cool: it's aging more slowly.  这就是最酷的地方：它衰老得更慢

　　It takes this worm two days  达到正常线虫衰老一天的程度

　　to age as much as the normal worm ages in one day.  它们需要两天时间

　　And when I tell people about this,  而我告诉其他人这件事的时候

　　they tend to think of maybe an 80 or 90 year-old person  他们认为也许这就像一个八九十岁的人

　　who looks really good for being 90 or 80.  看起来身体仍然硬朗一样

　　But it's really more like this:  但是其实更像这样：

　　let's say you're a 30 year-old guy -- or in your 30s --  如果你是个30岁、30多岁的单身汉

　　and you're a bachelor and you're dating people.  你去和别人约会

　　And you meet someone you really like, you get to know her.  然后你见到了一个中意的女孩，想多了解她

　　And you're in a restaurant, and you say, "Well how old are you?"  在饭桌上，你问她，“你多大了？”

　　She says, "I'm 60."  她说，“我60岁”

　　That's what it's like. And you would never know.  就像这样。你根本不知道

　　You would never know, until she told you.  根本不知道她有多大，要不是她告诉你的话