Hendrik Poinar: Bring back the woolly mammoth!

Translator: Joseph Geni Reviewer: Morton Bast

翻译人员: Li Li 校对人员: Yuzhou Yang

When I was a young boy,

当我还是个男孩时

I used to gaze through the microscope of my father

我经常从爸爸的显微镜里观察

at the insects in amber that he kept in the house.

他放在家里琥珀中的虫子

And they were remarkably well preserved,

它们保存得很好

morphologically just phenomenal.

看上去挺壮观的

And we used to imagine that someday,

我们曾幻想某天

they would actually come to life

他们会在现实中复苏

and they would crawl out of the resin,

并爬出这些树脂

and, if they could, they would fly away.

或许还会飞走

If you had asked me 10 years ago whether or not

十年前如果你问我

能否找出这种灭绝了的生物的基因排序

we would ever be able to sequence the genome of extinct animals,

I would have told you, it's unlikely.

我会告诉你，这不大可能

如果你问我

If you had asked whether or not we would actually be able

to revive an extinct species,

我们能否让灭绝的物种复活

我会告诉你，呵呵

I would have said, pipe dream.

But I'm actually standing here today, amazingly,

但我今天站在这里

想告诉你们，在当今现实中

to tell you that not only is the sequencing

of extinct genomes a possibility, actually a modern-day reality,

不单有望排列出绝种生物的基因

but the revival of an extinct species is actually within reach,

而且复活灭绝的生物也是可以办到的

maybe not from the insects in amber --

或许不是琥珀中的昆虫

in fact, this mosquito was actually used

事实上这种蚊子

for the inspiration for "Jurassic Park" —

曾给《侏罗纪公园》灵感

but from woolly mammoths, the well preserved remains

但从猛犸象

从永久冻土内保存完好的遗迹中可以看出

of woolly mammoths in the permafrost.

Woollies are a particularly interesting,

猛犸象是冰川时期

quintessential image of the Ice Age.

精萃和有趣的代表

They were large. They were hairy.

他们体型庞大，浑身毛茸茸

They had large tusks, and we seem to have

他们有硕大的獠牙，而且似乎人类和他们关系很密切

a very deep connection with them, like we do with elephants.

就像我们和大象的关系一样

Maybe it's because elephants share

或许是因为大象

many things in common with us.

和我们有很多共同点

They bury their dead. They educate the next of kin.

他们掩埋逝者，他们养育后代

They have social knits that are very close.

有着紧密的群体关系

Or maybe it's actually because we're bound by deep time,

又或许是因为我们有着很长的历史

because elephants, like us, share their origins in Africa

因为在几百万年前，和我们一样

大象的起源也是在非洲

some seven million years ago,

and as habitats changed and environments changed,

随着栖息地和环境的改变

we actually, like the elephants, migrated out

我们像大象一样迁徙

into Europe and Asia.

迁到欧洲和亚洲

So the first large mammoth that appears on the scene

所以世上的第一头猛犸象

is meridionalis, which was standing four meters tall

是南方猛犸，有四米高

weighing about 10 tons, and was a woodland-adapted species

约十吨重，而且是能适应林地的物种

and spread from Western Europe clear across Central Asia,

然后从西欧跨过中亚

across the Bering land bridge

跨过白令陆桥

and into parts of North America.

到达北美地区

And then, again, as climate changed as it always does,

随后由于常见的气候变化

and new habitats opened up,

新的栖息地也随之出现

we had the arrival of a steppe-adapted species

所以我们有了能在中亚适应草原的猛犸物种

called trogontherii in Central Asia

叫草原猛犸

pushing meridionalis out into Western Europe.

所以猛犸就从南方迁移到西欧

And the open grassland savannas of North America

广阔的北美热带稀树草原也成为新栖息地

opened up, leading to the Columbian mammoth,

在这里有了哥伦比亚猛犸

a large, hairless species in North America.

一种在北美的大型少毛猛犸

And it was really only about 500,000 years later

仅仅50万年后

that we had the arrival of the woolly,

一种猛犸出现了

the one that we all know and love so much,

就是那种我们熟知并喜爱的

spreading from an East Beringian point of origin

从东白令陆桥作为起点

across Central Asia, again pushing the trogontherii

跨过中亚，将草原猛犸

out through Central Europe,

推向中欧地区

and over hundreds of thousands of years

再经过数百年的演变

migrating back and forth across the Bering land bridge

在冰川时期

during times of glacial peaks

不断从白令陆桥来回往返

and coming into direct contact

终于和栖息在南边的哥伦比亚种族

with the Columbian relatives living in the south,

有了直接的联系

and there they survive over hundreds of thousands of years

并且他们在恶劣的气候变化下

during traumatic climatic shifts.

存活了成千上万年

So there's a highly plastic animal dealing with great transitions

所以这是一种适应性极高的

in temperature and environment, and doing very, very well.

能适应恶劣气候环境的动物

And there they survive on the mainland until about 10,000 years ago,

直到一万年前，他们才从这个陆地上消失

and actually, surprisingly, on the small islands off of Siberia

事实上，很令人惊讶的是，在西伯利亚周边的一些小岛上

and Alaska until about 3,000 years ago.

和在阿拉斯加那，他们3000年前才消失

So Egyptians are building pyramids

所以埃及人在建造金字塔时

and woollies are still living on islands.

猛犸象还在岛上生活着

And then they disappear.

之后他们才消失的

Like 99 percent of all the animals that have once lived,

像99%曾经存活过的动物一样

they go extinct, likely due to a warming climate

他们灭绝很可能是由于气候的暖化

and fast-encroaching dense forests

和在北迁过程中

that are migrating north,

迅速生长起来的森林

and also, as the late, great Paul Martin once put it,

另外，正如已故的伟大保罗马丁曾经指出

probably Pleistocene overkill,

很可能是“更新世时期”将他们赶尽杀绝

so the large game hunters that took them down.

强大的猎人将他们都干掉了

Fortunately, we find millions of their remains

幸运的是，我们找到数以万计的遗骸

strewn across the permafrost buried deep

散布在斯伯利亚和阿拉斯加

in Siberia and Alaska, and we can actually go up there

深埋的永久冻土内，所以我们可以到那里

and actually take them out.

将它们取出来

And the preservation is, again,

同样，对它们的保护也是完善的

like those insects in [amber], phenomenal.

就像那些琥珀中的昆虫一样

So you have teeth, bones with blood

所以你能看到牙齿，带血迹的骨头

which look like blood, you have hair,

看起来像血，你也能看到毛发

and you have intact carcasses or heads

还能看到完整的尸体

which still have brains in them.

或是仍有大脑在内的头部

So the preservation and the survival of DNA

保护措施和DNA的存活将依靠很多方面因素

depends on many factors, and I have to admit,

另外我不得不承认

most of which we still don't quite understand,

还有很大一部分仍旧是未解之谜

but depending upon when an organism dies

但依据生物死亡的时间

and how quickly he's buried, the depth of that burial,

以及掩埋的速度和深度

the constancy of the temperature of that burial environment,

还有掩埋环境温度的稳定性

will ultimately dictate how long DNA will survive

我们可以从地质学角度的有效时间范围内

over geologically meaningful time frames.

得出DNA还能存活多久

And it's probably surprising to many of you

对这里的大多数人来说，这可能有些不可思议

sitting in this room that it's not the time that matters,

因为时间不是关键

it's not the length of preservation,

保存时间的长度也不是关键

it's the consistency of the temperature of that preservation that matters most.

关键是保存温度的稳定性

So if we were to go deep now within the bones

所以如果我们真要去深究那些

and the teeth that actually survived the fossilization process,

经历了石化过程的骨头和牙齿

the DNA which was once intact, tightly wrapped

那么那些曾经完整，被组蛋白紧裹的DNA

around histone proteins, is now under attack

将无疑暴露在细菌的威胁中

by the bacteria that lived symbiotically with the mammoth

这些细菌也是当初与猛犸象在世时

for years during its lifetime.

共生的细菌

So those bacteria, along with the environmental bacteria,

因此那些细菌，和其他环境细菌

free water and oxygen, actually break apart the DNA

游离水和氧气，其实会将DNA分解

into smaller and smaller and smaller DNA fragments,

分解成更小的DNA片段

until all you have are fragments that range

这些片段分布不均

from 10 base pairs to, in the best case scenarios,

小的才有10对碱基对，最好的情况下

a few hundred base pairs in length.

也只有几百对碱基对

So most fossils out there in the fossil record

所以化石记录那里大部分的化石

are actually completely devoid of all organic signatures.

其实都是完全无有机特征的

But a few of them actually have DNA fragments

只有很少的一部分

that survive for thousands,

有存活数千年的有DNA片段

even a few millions of years in time.

有的甚至有几百万年历史

And using state-of-the-art clean room technology,

利用最先进的净化室技术

we've devised ways that we can actually pull these DNAs

我们设计了不同方案从这些粘泥状物体中

away from all the rest of the gunk in there,

提取出这些DNA

and it's not surprising to any of you sitting in the room

如果我拿出一根猛犸骨或一颗牙齿

that if I take a mammoth bone or a tooth

然后提取它的DNA，我将得到猛犸的DNA

and I extract its DNA that I'll get mammoth DNA,

这对大家来说，不足为奇

but I'll also get all the bacteria that once lived with the mammoth,

但我同时也得到了与猛犸同时期的细菌

and, more complicated, I'll get all the DNA

应该说，我提取到了

that survived in that environment with it,

生存在那个时期的所有DNA

so the bacteria, the fungi, and so on and so forth.

还有细菌，真菌，还有杂七杂八的

Not surprising then again that a mammoth

另一件不足为奇的事是

preserved in the permafrost will have something

保存在冻土里的猛犸

on the order of 50 percent of its DNA being mammoth,

会有约50%的是属于自己的DNA

whereas something like the Columbian mammoth,

而像哥伦比亚猛犸

living in a temperature and buried in a temperate environment

生活在一种温度下，掩埋在自己温和的墓地里

over its laying-in will only have 3 to 10 percent endogenous.

却只有3%到10%属于自己的DNA

But we've come up with very clever ways

然而我们想出了巧妙的方法

that we can actually discriminate, capture and discriminate,

我们其实能够区别，捕捉区别

the mammoth from the non-mammoth DNA,

哪些是猛犸的DNA

and with the advances in high-throughput sequencing,

加上高通量测序的帮助

we can actually pull out and bioinformatically

我们能够提取出

re-jig all these small mammoth fragments

并从生物信息角度重新加工这些小DNA片段

and place them onto a backbone

然后植入亚洲象或非洲象

of an Asian or African elephant chromosome.

的染色体主链上

And so by doing that, we can actually get all the little points

这样做，我们就能得到这些小点

that discriminate between a mammoth and an Asian elephant,

来区别猛犸和亚洲象

and what do we know, then, about a mammoth?

那么，我们能从猛犸身上了解到什么呢？

Well, the mammoth genome is almost at full completion,

其实，猛犸的基因组基本是排满的

and we know that it's actually really big. It's mammoth.

它确实很大，毕竟是猛犸嘛

So a hominid genome is about three billion base pairs,

原始人的基因大概有30亿对碱基对

but an elephant and mammoth genome

但是大象和猛犸的基因

is about two billion base pairs larger, and most of that

约多出20亿对碱基对

is composed of small, repetitive DNAs

大部分是由小而重复的DNA组成的

that make it very difficult to actually re-jig the entire structure of the genome.

这使得重组整个基因组变得十分困难

So having this information allows us to answer

所以拥有这些信息，我们就能够

one of the interesting relationship questions

解答那有趣的种族问题

between mammoths and their living relatives,

包括猛犸之间，和它们如今在世的近亲

the African and the Asian elephant,

那些非洲象亚洲象

all of which shared an ancestor seven million years ago,

所有那些七百万年前都是一家人的象

but the genome of the mammoth shows it to share

但是猛犸的基因显示

a most recent common ancestor with Asian elephants

它和亚洲象有着最近的共同祖先

about six million years ago,

约在六百万年前

so slightly closer to the Asian elephant.

所以多少和亚洲象比较亲近

With advances in ancient DNA technology,

在研究古代DNA技术的帮助下

we can actually now start to begin to sequence

我们现在已经能开始重组

the genomes of those other extinct mammoth forms that I mentioned,

其他灭绝了的猛犸物种的基因

and I just wanted to talk about two of them,

我在这里就提两种

the woolly and the Columbian mammoth,

长毛猛犸和哥伦比亚猛犸

both of which were living very close to each other

在冰川时期

during glacial peaks,

两种生活得非常近

so when the glaciers were massive in North America,

当北美的冰川还是很庞大的时候

the woollies were pushed into these subglacial ecotones,

长毛猛犸就被推进冰川下的过渡带

and came into contact with the relatives living to the south,

来到南边，接触到了其他种族

and there they shared refugia,

他们一同避难

and a little bit more than the refugia, it turns out.

慢慢地，就不止避难了

It looks like they were interbreeding.

似乎他们还相互交配繁殖

And that this is not an uncommon feature

这在长鼻类动物中不是新鲜事

in Proboscideans, because it turns out

因为发现

that large savanna male elephants will outcompete

大型的热带草原公象

the smaller forest elephants for their females.

比稍小的森林象更会求偶

So large, hairless Columbians

所以硕大的，无毛的哥伦比亚猛犸

outcompeting the smaller male woollies.

完胜稍小的公长毛猛犸

It reminds me a bit of high school, unfortunately.

这让我不禁想起高中的时候

(Laughter)

（笑声）

So this is not trivial, given the idea that we want

这其实很重要

to revive extinct species, because it turns out

因为我们要复活灭绝的种类

that an African and an Asian elephant

因为我们发现非洲象和亚洲象

can actually interbreed and have live young,

是能够杂交产生后代的

and this has actually occurred by accident in a zoo

这在1978年的英国切斯特的一座公园里

in Chester, U.K., in 1978.

是有发生过的

So that means that we can actually take Asian elephant chromosomes,

这就意味着我们能把亚洲象的染色体

modify them into all those positions we've actually now

嵌入到我们目前能够与猛犸基因区别开来

been able to discriminate with the mammoth genome,

的所有基因位置

we can put that into an enucleated cell,

我们可以将它放入一个无核的细胞中

differentiate that into a stem cell,

分化为一个干细胞

subsequently differentiate that maybe into a sperm,

然后或许再分化为一个精子

artificially inseminate an Asian elephant egg,

人工授精到亚洲象的卵子里

and over a long and arduous procedure,

在经过一个漫长艰苦的过程

actually bring back something that looks like this.

我们弄出了这么一个东西

Now, this wouldn't be an exact replica,

确切来说，这不是一个精确复制品

because the short DNA fragments that I told you about

因为我提到的短DNA片段

will prevent us from building the exact structure,

会妨碍我们构建真实的结构

but it would make something that looked and felt

但我们还是做出来看起来感觉起来

very much like a woolly mammoth did.

都很像长毛猛犸的生物

Now, when I bring up this with my friends,

当我把这个给朋友看的时候

we often talk about, well, where would you put it?

我们经常会谈到，不错，但你能把它放在哪啊？

Where are you going to house a mammoth?

你打算把它关在哪里啊？

There's no climates or habitats suitable.

我们没有合适的气候和住所啊

Well, that's not actually the case.

好吧，其实这些都不是问题

It turns out that there are swaths of habitat

我们发现在北西伯利亚和育空地区

in the north of Siberia and Yukon

有成片的栖息地

that actually could house a mammoth.

那里可以给猛犸生活

Remember, this was a highly plastic animal

记住，这是一种经历过无数天云变幻气候

that lived over tremendous climate variation.

的高适应性生物

So this landscape would be easily able to house it,

所以它们能很容易适应这个地方

and I have to admit that there [is] a part of the child in me,

我必须承认，我不会像小孩一样幼稚地说

the boy in me, that would love to see

我很想再次看到

these majestic creatures walk across the permafrost

这些庄严宏伟的生物

of the north once again, but I do have to admit

横跨北边的冻土，但我得承认

that part of the adult in me sometimes wonders

成人的理智仍时不时让我纠结

whether or not we should.

我们是否应该这么做

Thank you very much.

非常感谢

(Applause)

（掌声）

Ryan Phelan: Don't go away.

Ryan Phelan: 先别急着走

You've left us with a question.

你留给了我们一个问题

I'm sure everyone is asking this. When you say, "Should we?"

我确定每个人都想问，当你说“我们应该吗？”时

it feels like you're reticent there,

你似乎有些不确定

and yet you've given us a vision of it being so possible.

但是你又向我们展示了它是及其可能的

What's your reticence?

你为什么有些不确定？

Hendrik Poinar: I don't think it's reticence.

我不觉得是不确定

I think it's just that we have to think very deeply

我觉得只是我们需要深入的思考

about the implications, ramifications of our actions,

我们行动的意义和影响

and so as long as we have good, deep discussion

只要我们继续有良好并深入的讨论我们为什么这么做

like we're having now, I think

就像我们现在这样

we can come to a very good solution as to why to do it.

我们会有一个好的答案

But I just want to make sure that we spend time

我只想确定在我们付诸实践之前

thinking about why we're doing it first.

花足够的时间去思考这么做的原因

RP: Perfect. Perfect answer. Thank you very much, Hendrik.

完美的回答谢谢你，Hendrik

HP: Thank you. (Applause)

谢谢（掌声）