but we haven't always been that good at figuring out what's important.

卻總是找錯重點。

Take the ancient Egyptians, for example:

以古埃及人為例：他們非常重視

very concerned about the body parts they thought they'd need in the afterlife,

身體的各個部位，因為這將是 他們來世的軀體，

but they left some parts out.

但仍會有的放矢。

This part, for example.

以此為例。

Although they very carefully preserved the stomach, the lungs,

古埃及人會謹慎處理胃、肺

the liver, and so forth,

肝等器官，

they just mushed up the brain, drained it out through the nose,

但對於頭部，他們只會沖洗鼻腔，

and threw it away,

然後就隨便處理掉了，

which makes sense, really,

這樣的作法合理的，

because what does a brain do for us anyway?

想想大腦對我們的幫助為何就知道了？

But imagine if there were a kind of neglected organ in our bodies

但試想如果我們所忽視 的一個體內器官

that weighed just as much as the brain

它的重量恰巧和大腦相同

and in some ways was just as important to who we are,

決定我們會成為怎樣的人，

but we knew so little about and treated with such disregard.

但因為我們的無知而被打入冷宮。

And imagine if, through new scientific advances,

再試想，如果隨著科技的不斷進步

we were just beginning to understand

我們開始注意到

its importance to how we think of ourselves.

原來它對我們如此重要。

Wouldn't you want to know more about it?

你還會繼續對它視而不見嗎？

Well, it turns out that we do have something just like that:

我想，接下來你可能會：

our gut,

開始關注我們的腸道

or rather, its microbes.

或更多東西，比如腸道中的微生物。

But it's not just the microbes in our gut that are important.

當然不是只有腸道中的 微生物值得關注。

Microbes all over our body

它無處不在，遊走于我們體內，

turn out to be really critical to a whole range of differences

是造成人體差異，

that make different people who we are.

形成不同個體的關鍵因素。

So for example, have you ever noticed

舉例來說，你有沒有發現

how some people get bitten by mosquitos way more often than others?

有些人就是特別容易被蚊蟲叮？

It turns out that everyone's anecdotal experience out camping is actually true.

事實上每個人的露營 經驗談都沒有造假。

For example, I seldom get bitten by mosquitos,

拿我來說，蚊子很少叮我，

but my partner Amanda attracts them in droves,

但我的太太阿曼達是牠們的最愛，

and the reason why is that we have different microbes on our skin

原因就是我倆表皮上的 微生物形成了

that produce different chemicals that the mosquitos detect.

不同的化學物質，導致 蚊蟲的反應不同。

Now, microbes are also really important in the field of medicine.

目前，微生物對醫療也 發揮著重要作用。

So, for example, what microbes you have in your gut

比如，腸道中的微生物能判斷

determine whether particular painkillers are toxic to your liver.

某些止痛劑對肝臟是否 有毒副作用。

They also determine whether or not other drugs will work for your heart condition.

它們還能判斷其它藥物是否會 影響你的心臟功能。

And, if you're a fruit fly, at least,

如果你是只果蠅，微生物至少

your microbes determine who you want to have sex with.

能決定你嚮往的交配對象。

We haven't demonstrated this in humans yet

當然對於人類尚未明斷

but maybe it's just a matter of time before we find out. (Laughter)

但相信有一天我們會 找到答案（笑聲）

So microbes are performing a huge range of functions.

所以，微生物的作用很多。

They help us digest our food.

它們有助於食物消化。

They help educate our immune system.

可以錘煉我們的免疫系統。

They help us resist disease,

還能幫助我們抵抗疾病，

and they may even be affecting our behavior.

甚至會影響我們的行為。

So what would a map of all these microbial communities look like?

那麼這些微生物群落 有著怎樣的結構呢？

Well, it wouldn't look exactly like this,

我想不太會像這樣，

but it's a helpful guide for understanding biodiversity.

但我們可以藉此 了解生物多樣性。

Different parts of the world have different landscapes of organisms

不同的地方正因為

that are immediately characteristic of one place or another

有了不同的生物體

or another.

才賦予了他們獨有的特色。

With microbiology, it's kind of the same, although I've got to be honest with you:

對於微生物界，道理相同， 但我也必須承認：

All the microbes essentially look the same under a microscope.

它們在顯微鏡下看起來都一樣。

So instead of trying to identify them visually,

所以，既然無法從 視覺上區分他們，

what we do is we look at their DNA sequences,

那麼我們只能從 基因序列來辨別，

and in a project called the Human Microbiome Project,

在一項名為人類微生物組 項目的計劃中，

NIH funded this $173 million project

NTH 投資了 17300 萬美元，

where hundreds of researchers came together

同時該項目還吸引到了 數百位研究人員

to map out all the A's, T's, G's, and C's,

為的是弄清所有A's、 T's、 G's和C's

and all of these microbes in the human body.

以及人體內所有微生物 的排列組合。

So when we take them together, they look like this.

結果我們看到了 這樣一幅景象。

It's a bit more difficult to tell who lives where now, isn't it?

這樣你很難看出它們 的具體位置，對嗎？

What my lab does is develop computational techniques that allow us

我的實驗室為此開發 了一種計算技術

to take all these terabytes of sequence data

可將序列數據取值 到兆兆字節

and turn them into something that's a bit more useful as a map,

同時排列組合成可用性 更高的圖譜樣式，

and so when we do that with the human microbiome data

所以如果我們將250名 健康的志願受試者

from 250 healthy volunteers,

體內的微生物數據代入其中，

it looks like this.

會顯示這樣的圖譜。

Each point here represents all the complex microbes

這其中的每個點都代表整個

in an entire microbial community.

微生物群落中各個複雜的微生物。

See, I told you they basically all look the same.

就像我說的，它們的樣子 都差不多。

So what we're looking at is each point represents one microbial community

所以我們的觀察重點是 每個點是代表一位健康

from one body site of one healthy volunteer.

志願受試者的某個軀體部位 的一個微生物群落。

And so you can see that there's different parts of the map in different colors,

我們像區分大陸板塊一樣， 用不同顏色

almost like separate continents.

在圖譜中標識不同部位。

And what it turns out to be

由此可以發現

is that those, as the different regions of the body,

在軀體不同區域

have very different microbes in them.

會聚集不同的微生物。

So what we have is we have the oral community up there in green.

現在我們看到的綠色群落 是口腔微生物群落。

Over on the other side, we have the skin community in blue,

在另一邊藍色的群落是 肌膚的微生物群落，

the vaginal community in purple,

紫色的是陰道微生物群落，

and then right down at the bottom, we have the fecal community in brown.

而在右下方棕色的是 肛腸區的微生物群落。

And we've just over the last few years

近幾年來，我們驚奇地發現

found out that the microbes in different parts of the body

人體不同部位的微生物

are amazingly different from one another.

竟然各不相同。

So if I look at just one person's microbes

所以，如果我們觀察一個人口腔和

in the mouth and in the gut,

腸道中的微生物，

it turns out that the difference between those two microbial communities

會發現這兩個部位的微生物群落

is enormous.

的差異相當大。

It's bigger than the difference between the microbes in this reef

人體中微生物群落的差異比

and the microbes in this prairie.

暗礁和草原微生物群落的差異更大。

So this is incredible when you think about it.

細想真是不可思議。

What it means is that a few feet of difference in the human body

這表示如果從微生物生態學來看，

makes more of a difference to your microbial ecology

人體中微生物存在的些許差異

than hundreds of miles on Earth.

轉變為地球生態，其差異 可以是天差地別的。

And this is not to say that two people look basically the same

也就是說，兩個看似相同的人

in the same body habitat, either.

未必有相同的體內環境。

So you probably heard

你可能聽過這樣的說法

that we're pretty much all the same in terms of our human DNA.

如果從人類的 DNA 來看， 每個人都幾近相同。

You're 99.99 percent identical in terms of your human DNA

以 DNA 來說，你和

to the person sitting next to you.

隔壁的人相似度可達 99.99%。

But that's not true of your gut microbes:

但是說道腸道微生物就不一樣了：

you might only share 10 percent similarity

從腸道微生物的角度來看，

with the person sitting next to you in terms of your gut microbes.

相鄰兩人的相似度可能僅有10%。

So that's as different as the bacteria on this prairie

這就好比草原中存活的細菌

and the bacteria in this forest.

不同於森林中存活的細菌。

So these different microbes

如同我之前提到的， 正是這些各不相同的微生物

have all these different kinds of functions that I told you about,

在人體中產生了不同的功用，

everything from digesting food

從消化食物

to involvement in different kinds of diseases,

到影響各類病症、

metabolizing drugs, and so forth.

代謝藥物等等。

So how do they do all this stuff?

那麼微生物是如何 集結成群，發揮作用的？

Well, in part it's because

一方面是因為，

although there's just three pounds of those microbes in our gut,

這些僅重三磅的腸道衛生物

they really outnumber us.

其實際數目卻是驚人的。

And so how much do they outnumber us?

你問數目有多驚人？

Well, it depends on what you think of as our bodies.

這取決於你怎麼看待人體。

Is it our cells?

如果你支持細胞論？

Well, each of us consists of about 10 trillion human cells,

那麼每個人都是由約10萬億 個人體細胞組成的，

but we harbor as many as 100 trillion microbial cells.

而我們體內存有的微生物細胞 達100萬億個。

So they outnumber us 10 to one.

也就是說相當於10個我們。

Now, you might think, well, we're human because of our DNA,

當然，如果你推崇DNA的概念，

but it turns out that each of us has about 20,000 human genes,

那麼目前已知的確切數字是，

depending on what you count exactly,

我們體內的遺傳因子約為20,000個，

but as many as two million to 20 million microbial genes.

而微生物基因的數量可達 200萬至2000萬個。

So whichever way we look at it, we're vastly outnumbered

所以無論是支持哪種理論，

by our microbial symbionts.

我們都是由無數的 微生物共生體組成的。

And it turns out that in addition to traces of our human DNA,

所以我們不但要研究人類的DNA，

we also leave traces of our microbial DNA

我們所接觸對象的

on everything we touch.

微生物DNA也是有待挖掘的領域。

We showed in a study a few years ago

我們在過去幾年進行的研究顯示，

that you can actually match the palm of someone's hand up

如將某人留在常用鼠標上的物質

to the computer mouse that they use routinely

與其本身的掌紋相比較，

with up to 95 percent accuracy.

其匹配率可高達95%。

So this came out in a scientific journal a few years ago,

數年前曾有科學雜誌報道過這項發現，

but more importantly, it was featured on "CSI: Miami,"

不過美國影集“CSI：邁阿密系列” 令它街知巷聞，

so you really know it's true.

可見這不是編劇杜撰的。

(Laughter)

（大笑）

So where do our microbes come from in the first place?

那麼微生物從何而來？

Well if, as I do, you have dogs or kids,

像我一樣，如果你有養狗或小孩，

you probably have some dark suspicions about that,

可能難免會對此產生些 邪惡的疑慮，

all of which are true, by the way.

順便一提，這都說得通。

So just like we can match you to your computer equipment

正如我們可以將你 留在計算機設備上的

by the microbes you share,

的微生物與本體作比較，

we can also match you up to your dog.

同樣的結果也可以印證在狗的身上。

But it turns out that in adults,

結果我們發現，成人的微生物群落

microbial communities are relatively stable,

相對穩定。

so even if you live together with someone,

所以即使你和某人生活在一起，

you'll maintain your separate microbial identity

仍可維持數週、數月、甚至數年

over a period of weeks, months, even years.

你獨有的微生物特性。

It turns out that our first microbial communities

也就是說我們最初的微生物群落

depend a lot on how we're born.

取決於我們的出生環境。

So babies that come out the regular way,

所以，對於順產的寶寶

all of their microbes are basically like the vaginal community,

他們的微生物特性通常更接近 於陰道部位的群落特征，

whereas babies that are delivered by C-section,

而剖腹產的寶寶，

all of their microbes instead look like skin.

其微生物特性更接近于 肌膚的微生物群落。

And this might be associated with some of the differences

而這種差異也可能被認為與

in health associated with Cesarean birth,

剖腹產寶寶的體質健康有關聯，

such as more asthma, more allergies, even more obesity,

比如目前就有較多人 認為微生物可能

all of which have been linked to microbes now,

與哮喘、過敏甚至是肥胖症有關，

and when you think about it, until recently, every surviving mammal

基於這一點，反觀直至目前，

had been delivered by the birth canal,

每個經產道分娩的哺乳動物，

and so the lack of those protective microbes

以及所缺少的、

that we've co-evolved with might be really important

共同進化、起保護作用的微生物，

for a lot of these different conditions that we now know involve the microbiome.

可能正是催生出不同 微生物學條件的重要因素。

When my own daughter was born a couple of years ago

幾年前我太太在緊急情況下

by emergency C-section,

剖腹產下我的女兒，

we took matters into our own hands

我們只能自食其力

and made sure she was coated with those vaginal microbes

後天給予女兒如同順產般

that she would have gotten naturally.

可受到的陰道微生物群的保護。

Now, it's really difficult to tell whether this has had an effect

目前，我們尚無法判斷

on her health specifically, right?

這對她的健康是否有用，不是嗎？

With a sample size of just one child, no matter how much we love her,

我們的觀察樣本只有一個孩子， 無論我們多愛她，

you don't really have enough of a sample size

我們還是缺少足夠的觀察樣本，

to figure out what happens on average,

推斷出平均水平，

but at two years old, she hasn't had an ear infection yet,

直到她兩歲時， 尚未患支氣管炎，

so we're keeping our fingers crossed on that one.

為此我們也一直祈禱她健康。

And what's more, we're starting to do clinical trials with more children

同時我們也開始通過臨床試驗 觀察其他孩子，

to figure out whether this has a protective effect generally.

藉此判斷這種微生物 是否能起到一般保護作用。

So how we're born has a tremendous effect on what microbes we have initially,

可見分娩方式不同， 初生時體內微生物的不同，

but where do we go after that?

其影響也是巨大的， 那麼接下來我們該做什麼？

What I'm showing you again here is this map

這裡我將再次出示這張

of the Human Microbiome Project Data,

人體微生物項目數據圖譜，

so each point represents a sample from one body site

圖譜中的每個點都 代表 250 位健康成年人

from one of 250 healthy adults.

各個身體部位的取樣結果。

And you've seen children develop physically.

各位已經熟悉兒童的生理發育，

You've seen them develop mentally.

也瞭解他們的心理成長，

Now, for the first time, you're going to see

現在，你們將首次見證

one of my colleague's children develop microbially.

我同事的一個孩子 在微生物意義上的蛻變。

So what we are going to look at

我們接下來要觀察的對象

is we're going to look at this one baby's stool,

就是這個孩子的“粑粑”,

the fecal community, which represents the gut,

即代表腸道的糞便菌落，

sampled every week for almost two and a half years.

我們每週採樣，持續近兩年半時間。

And so we're starting on day one.

我們從第一天開始觀察，

What's going to happen is that the infant is going to start off as this yellow dot,

這個黃球的運動軌跡 就是嬰兒的微生物發育過程，

and you can see that he's starting off basically in the vaginal community,

它基本上從陰道菌落開始出發，

as we would expect from his delivery mode.

這也符合孩子的分娩方式。

And what's going to happen over these two and a half years

在兩年半的時間裡，

is that he's going to travel all the way down

它由上而下運動，

to resemble the adult fecal community from healthy volunteers down at the bottom.

最終與底部的健康志願者 糞便菌落相吻合。

So I'm just going to start this going and we'll see how that happens.

我們來看這一運動過程是怎樣的。

What you can see, and remember each step in this is just one week,

請注意，黃球的每一步移動都歷時一周，

what you can see is that week to week,

大家可以看到這個孩子

the change in the microbial community of the feces of this one child,

糞便微生物菌落的每週變化情況，

the differences week to week are much greater

這種變化遠遠超出了

than the differences between individual healthy adults

人類微生物菌落專案對列中

in the Human Microbiome Project cohort,

健康成人個體之間的差異。

which are those brown dots down at the bottom.

底部的褐色球表示 成人個體的微生物菌落。

And you can see he's starting to approach the adult fecal community.

我們可以看到， 它正開始接近成人糞便菌落。

This is up to about two years.

此時已過去了近兩年時間。

But something amazing is about to happen here.

但一場“奇跡”即將在這裡上演。

So he's getting antibiotics for an ear infection.

孩子因為耳部感染而服用了抗生素，

What you can see is this huge change in the community,

這導致其微生物菌落發生巨變，

followed by a relatively rapid recovery.

接著是相對快速的修復。

I'll just rewind that for you.

我們再來看一遍。

And what we can see is that just over these few weeks,

經過短短幾周時間，

we have a much more radical change,

我們發現微生物菌落的變化越來越大，

a setback of many months of normal development,

拖累了孩子數個月的正常發育，

followed by a relatively rapid recovery,

接下來是相對快速的修復，

and by the time he reaches day 838,

等到第838天，