And these are your ancestors, a huge pyramid stretching into the past and balancing right

而這些是你的祖先，一個巨型的金字塔連結著過去和

on your head.

從你開始的左右平衡

How many ancestors do you have?

你有多少祖先呢？

Well, you have two parents.

你有一對父母親

Four grandparents.

四位祖父母

And eight great-grandparents.

以及八位曾祖父母

Four generations back, your direct ancestors total 30.

連結四個世代以後，和你直接相連的祖先一共有 30 位

If we continue down this line, doubling every step, just 40 generations ago we’d find

如果我們朝著這方向下去，每隔兩代，到了第40代以後我們會發現

a trillion ancestors, all living *at the same time*.

一兆位祖先同時生活在一起

Which is… ridiculous.

這…聽起來很不可思議

That's not only more people than have ever been alive, it's more stars than are in

這不僅超越世界上人類生存的數目，這比銀河系上的星星

the Milky Way.

還要多

Since our species came on the scene 200,000 years ago, there have been maybe 7 or 8 *thousand*

我們人類是二十萬年前出現，所以可能經歷了七千或八千

generations of humans leading up to… you.

個世代來到現在的你

So where are all your missing ancestors?

那麼那些遺失的祖先去哪了呢？

Clearly, there’s been some inbreeding.

很明顯的，有些是近親交配

[OPEN]

We’re not talking banjo-playing, King-of-Spain, Cersei-Jaime inbreeding, but every family

我們並不是要談論彈琵琶、西班牙國王或者是瑟曦潔米的亂倫，但每個

tree inevitably grows forks.

家族樹無可避免由這種方式開枝散葉

Before Tinder, choices for mates were often limited to as far as you could walk.

在有Tinder (交友軟體) 之前，選擇伴侶僅限於你行動的距離

Even people like Charles Darwin and Albert Einstein married their first cousins.

連查爾斯達爾文和亞博愛因斯坦都和他們第一代的親戚結婚

Because so many people with shared ancestors have reproduced, our number of actual ancestors

因為許多人有著相同的祖先，所以祖先的真實數字

is much smaller than what simple math tells us.

遠小於我們算數告訴我們的

If we replace that with fancy math, factoring in how people moved and lived and paired up…

如果我們用這個取代數學邏輯，著重在人們遷徙居住並配對…

life expectancy, trade, geography, Genghis Khan… we find something interesting: every

生活的預期，貿易，地理，成吉思汗…我們會發現有趣的事情：

human alive today shares a common ancestor in their family tree, and this person lived

活在當今現代的人們有著共同的祖先在家族樹上，而這位祖先

only around 3,000 years ago.

是距今三千年以前

That’s right, next time you get in a fight with a stranger on the internet, just remember

這就對了，下次你在網路上和陌生人開始爭論時，要記得

that you share the same great great great great great (fast foward) great grandfather

你們有著共同的曾曾曾曾曾(快轉) 曾祖父

or grandmother.

或祖母

But we don’t know who that person was.

但我們都不知道那位是誰

The math tells us they must have existed, but they didn’t leave fossils or artifacts.

數學告訴我們他們一定存在，但他們並沒有留下化石或手工藝品

Or like, a note or something.

或筆記之類的

Though, writing birthday cards for each of their 7.4 Billion great great great great

然而，寫生日卡片給他們 74 億位的曾曾曾曾

great (fast forward) great grandchildren would have been nice gesture.

曾（快轉）曾孫可能會是一個好的方法

But we all carry a record of our ancestors in our genes.

但在我們的基因裡面有著我們祖先的影子

Because DNA is copied over and over, every so often a mistake is written in.

而 DNA 是一直重覆複製，所以有些錯誤也會被一同移植過來

You know how when you make a copy of a copy, it’s doesn't come out as sharp?

你知道每當你再複製一次，東西會變得更加模糊?

Like that, but since most of our DNA can be changed without affecting how things work,

就是如此，由於我們大部分的 DNA 可以被改變而不影響事情的運作方式

many of these mutations slip through to the next generation.

許多這些突變也會移轉到下一代

These genetic changes accumulate at a steady rate through time, so scientists can read

這些基因的改變會隨著時間的過去累積成一固定比例，科學家可以

them like a molecular clock, and estimate how much time has passed.

從這些數值做分子鐘的解讀，並去推算經歷多少時間

And which changes individuals share tell us how closely or distantly related they are.

而這些個體的改變告訴我們的關係多近或相隔幾代

Humans *seem* really different, but on a DNA level we’re remarkably similar.

人類「看似」非常不同，但在 DNA 我們其實是相同的

Groups of chimps in Central Africa, living right next to each other, show more genetic

中非黑猩猩群，他們住在彼此隔壁，展現了許多基因

variation than we find in the entire human population.

的變化遠比我們在全人類所發現

This genetic similarity tells us that our species is new, in the big scheme of things,

在整個大體系中，基因上的相似告訴我們人類還是新的物種

and that at one point our population was small, maybe as few as 10,000 of us.

而在某個層面上人類的數目算小，大概只有一萬個我們

To put that in perspective, that’s only a third of your average Bruce Springsteen

從這個觀點來看，這只是平均布魯斯·斯普林斯汀演唱會人數的三分之一

crowd.

而已

Sorry Boss.

Today, any two humans only differ by about 1 out of 1000 DNA base pairs.

今日，任何兩個人只有千分之一的機率有不同的 DNA

But our genome is so big, that’s still millions of single letter differences, or SNPs, for

但是我們基因組成是太大了，仍然是數以百萬計的單字母差異或，或 SNPs

“single nucleotide polymorphism”.

又稱「單核苷酸多態性」

We tend to see combinations of these changes, chunks of SNPs, associated with different

我們想要把這些改變組合在一起，大部份的 SNPs，是關係著不同的

geographic locations.

地理位置

Companies that test your DNA ancestry read thousands of these single letter changes in

檢測 DNA 的公司會運用基因組中數千種單位改變來找出你的祖先

your genome, to make a sort of signature of your unique genetic variation.

並根據結果訂出相關特徵，就是專屬你的基因變化

Then they compare your signature to thousands of reference individuals from various parts

之後他們用你的特徵來配對數千個來自世界上不同區塊的參考個體

of the world, and do a bunch of fancy math to see which parts of your genome most likely

並用高度技巧的數學來分析你的基因組

came from certain geographic areas.

可能來自於地球上哪個地方

My genetic results: Pretty much look like this.

我的基因結果：大概長得像這樣

My ancNewsprestors, on both sides of my family, are from Northern Europe and Scandinavia,

我的祖先，由父母兩方開始，都來自北歐和斯坎維尼亞

which explains my last name, why I’m tall, why I don’t tan, and also why I carry more

這就可以說明我的姓，為何我長的比較高，皮膚比較白和

Neanderthal DNA than 2/3rds of people.

相較於其他三分之二的人，我擁有尼安德塔爾人的 DNA

Confused why I have Neanderthal DNA?

疑惑我什麼擁有尼安德塔爾人的DNA？

You should watch our last video. I didn’t find any surprises, but many people learn

你應該要看上一部影片。我並沒有感到驚訝，但許多人認識

about ancestry they didn’t know they had.

這他們其實有這個血統而不自知

Where we come from isn’t always obvious on the outside, but DNA doesn’t lie.

我們並不會輕易的從外在了解到我們來自何方，而 DNA 結果是最真實的

Before, using math, we identified an ancestor, not too long ago, that’s related to all

以前我們可以運用數學，來分辨我們的祖先，在不久前，我們發現我們是有相關的

of us.

But that person’s genetic influence has been shuffled so much it’s invisible in

但那基因影響已經隨著時間逐漸改組，至今在我們的 DNA 裡已經看不到了

our DNA today.

Is there someone whose genes have been passed on, unbroken, to today?

有沒有誰的基因是經過時間更迭傳到今天呢？

Some leftover fingerprint from the mother of everyone alive?

有任何殘留的指紋是從母親那邊遺留下來的呢？

There is.

有的

You have a 47th chromosome.

你的第47個染色體

It lives in mitochondria, the POWERHOUSE OF THE CELL! – so we’re doing that again?

它住在線粒體。「細胞的動力！」，所以我們再來操作一次

Ok–mitochondria used to be free-swimming.

好的，線粒體一直都自由自在的

They have their own genetic material.

他們帶有自己的基因

Unlike your other 46 chromosomes, there’s no shuffling when it’s passed between generations.

不像其他的46個染色體，並沒有轉移到下個世代

What’s more, all your mitochondria came from your mother’s egg, not your father’s

況且，所有的線粒體都是來自於媽媽的卵子而不是爸爸的

sperm.

精子

They trace an unbroken line of ancestors stretching back through every female in your family tree.

他們可以延著這條線追溯到每位家族樹上的女性

By comparing the changes that have accumulated over the millennia, we find the most ancient

在累積數千年後，比對這些改變，我們發現最原始

human mitochondrial DNA comes from Africa, where our species originated.

人類的線粒體 DNA 是來自於非洲，這是所有物種的發源地

We can even trace it back to one woman, about 150,000 years ago.

我們也可以追溯到第一位女性，大約十五萬年前

Other Homo sapiens females lived alongside her, but only her lineage lives on today,

其他女性人種和她生活在一起，但只有他的血統遺留到至今

all other Homo sapiens lineages are extinct.

而其他的人種血統都絕跡了

This is mitochondrial Eve.

這就是線粒體的前世

And every single one of us, descend from her.

而我們每一位都是她的後繼者

In the truest sense, we really are family.

而事實上，我們都是一家人

Even if we’re just hundredth cousins or something.

即使我們是很遠房的親戚

But our ancestry isn’t just branches stretching into the past, it’s also a tree that extends

我們的祖先並不是只有過去的發展，也會連結到我們的未來

into the future.

Today we have more power to mold that future, down to the genetic level, than we’ve ever

現在我們比以前有更多的能力去影響未來，可以深至基因階段

had before.

So what might our species’ future look like?

那麼我們未來物種會長什麼樣子呢？

Next time.

下次

Stay curious.

持續保持著好奇心

This video is part of a special series we’re doing about the story of our species: Where

這影片是我們最近在做敘述物種的特輯之一：

we came from, how we’re all connected, and where we’re going.

我們從何而來？我們真的有關聯性？未來在哪裡？

If you haven’t already, check out part 1 and 2 to trace the fossils in our family tree

如果你不了解，先看看第一和第二部影片有關追溯家族樹的化石

and learn why we’re the only humans left.

和了解為什麼我們是唯一留下的人種

And be sure to subscribe so you don’t miss any of our videos.

並要訂閱頻道以免沒看到我們的影片喔