Clues to prehistoric times, found in blind cavefish | Prosanta Chakrabarty

譯者: Regina Chu 審譯者: SF Huang

Ichthyology,

魚類學，

the study of fishes.

是一門研究魚類的學科。

It looks like a big, boring word,

聽起來或許很籠統和無聊，

but it's actually quite exciting,

但是其實還滿有趣的，

because ichthyology is the only "ology"

因為魚類學這個單字，是所有學科中

with "YOLO" in it.

唯一包含 "YOLO" 的。 （譯註：美國俚語）

(Laughter)

（笑聲）

Now, to the cool kids in the audience,

台下走在潮流尖端的聽眾，

you already know, YOLO stands for "you only live once,"

你們一定知道 "YOLO" 指的是 「你只能活一次。」

and because I only have one life,

正因如此，

我決定去追求我的夢想，

I'm going to spend it doing what I always dreamt of doing:

seeing the hidden wonders of the world and discovering new species.

探索未知世界的奧妙，發現新物種。

And that's what I get to do.

那是我要做的。

Now, in recent years, I really focused on caves for finding new species.

這幾年來我致力於 尋找洞穴中的新物種。

And it turns out, there's lots of new cavefish species out there.

結果發現，在洞穴中 的確有大量的新魚種。

You just have to know where to look,

但是你得知道要去哪裡找，

and to maybe be a little thin.

而且你可能得瘦一點。

(Laughter)

（笑聲）

Now, cavefishes can tell me a lot about biology and geology.

洞穴魚其實可以告訴我們 許多生物學與地質學的故事。

They can tell me how the landmasses around them have changed and moved

透過牠們居住的小洞穴，

我們可以研究大陸板塊的 改變及漂移；

by being stuck in these little holes,

and they can tell me about the evolution of sight, by being blind.

透過牠們的盲眼， 讓我們了解到視覺的演化過程。

Now, fish have eyes that are essentially the same as ours.

魚和我們一樣都有眼睛， 所有脊椎動物都有。

All vertebrates do, and each time a fish species starts to adapt

當魚類為求生存，

to this dark, cold, cave environment,

而去適應黑暗、冰冷的洞穴環境，

over many, many generations, they lose their eyes and their eyesight

在經過世代的演化後， 牠們逐漸失去眼睛和視力，

until the end up like an eyeless cavefish like this one here.

最後，就像這條無眼的洞穴魚一樣。

Now, each cavefish species has evolved in a slightly different way,

每種洞穴魚的演化方式都不太一樣，

and each one has a unique geological and biological story to tell us,

而且每種都在訴說著 其獨特的生物、地質學故事。

and that's why it's so exciting when we find a new species.

這就是為什麼每當發現新的魚種， 都很振奮人心。

So this is a new species we described, from southern Indiana.

這隻就是我們說的新魚種， 在印地安那州南部發現。

我們命名為 "Amblyopsis hoosieri" 印地安那盲鱂。（笑聲）

We named it Amblyopsis hoosieri, the Hoosier cavefish.

(Laughter)

（譯註：印地安那州人俗稱 hoosier）

Its closest relatives are cavefishes in Kentucky,

牠的近親為肯塔基洞穴魚，

生活在猛獁洞穴系統內。

in the Mammoth Cave system.

And they start to diverge when the Ohio River split them

幾百萬年前， 因俄亥俄河而被分開的牠們，

a few million years ago.

開始演化分歧。

And in that time they developed these subtle differences

那段期間，牠們的遺傳結構 產生細微差異的演化，

in the genetic architecture behind their blindness.

造成其失明的原因也各異。

There's this gene called rhodopsin that's super-critical for sight.

有一種稱為視紫質的基因， 對於視覺超級重要。

We have it, and these species have it too,

我們都有這個，這兩個物種也有，

except one species has lost all function in that gene,

其中一個物種已經失去了 該基因的所有功能，

and the other one maintains it.

而另一物種還保有它。

So this sets up this beautiful natural experiment

此種自然界的美妙實驗，

where we can look at the genes behind our vision,

使我們可以觀察到 視覺背後的基因奧秘，

and at the very roots of how we can see.

及了解到視覺感知的根本原理。

但是，這些洞穴魚的基因，

But the genes in these cavefishes

can also tell us about deep geological time,

也提供了深邃地質年代的線索，

maybe no more so than in this species here.

大概沒有比這種物種更多了。

This is a new species we described from Madagascar

這個新物種來自馬達加斯加，

that we named Typhleotris mararybe.

我們將其命名為 "Typhleotris mararybe"，

That means "big sickness" in Malagasy,

馬拉加西語的意思就是「大病」，

for how sick we got trying to collect this species.

因為我們試圖採集該物種時， 都生了大病。

Now, believe it or not,

信不信由你，

swimming around sinkholes full of dead things

在滿布腐屍物的汙水坑和

and cave full of bat poop

充滿著蝙蝠大便的洞穴內游泳，

isn't the smartest thing you could be doing with your life,

實在不是一件明智之舉，

but YOLO.

但是，你只能活一次啊！

(Laughter)

（笑聲）

Now, I love this species despite the fact that it tried to kill us,

儘管這種魚差點害死我們， 我還是很愛牠。

and that's because this species in Madagascar,

因為這種生活在馬達加斯加的魚，

its closest relatives are 6,000 kilometers away,

最近的近親是遠在

六千公里外的澳洲的洞穴魚。

cavefishes in Australia.

Now, there's no way a three-inch-long freshwater cavefish

一條三英吋長的淡水洞穴魚，

can swim across the Indian Ocean,

是不可能游泳橫越印度洋的。

so what we found when we compared the DNA of these species

所以我們在比較 兩者的 DNA 後發現，

is that they've been separated for more than 100 million years,

牠們已經分開超過一億年，

or about the time that the southern continents were last together.

或者說是自南大陸板塊 漂移分裂後至今的時間。

So in fact, these species didn't move at all.

其實這兩種物種根本沒有搬家。

It's the continents that moved them.

是南大陸板塊移動了牠們。

And so they give us, through their DNA,

牠們的 DNA 給了我們

this precise model and measure

精確的模式及方法，

of how to date and time these ancient geological events.

為古代的地質事件定年、定時。

這個物種非常新，

Now, this species here is so new

I'm not even allowed to tell you its name yet,

我目前還不能公開牠的名字，

but I can tell you it's a new species from Mexico,

但是我可以告訴大家， 這是墨西哥新種，

and it's probably already extinct.

而且可能已經絕種了。

It's probably extinct because the only known cave system it's from

可能絕種，是因為我們 唯一知道可以發現牠的洞穴系統，

was destroyed when a dam was built nearby.

已經被附近的水壩工程摧毀了。

Unfortunately for cavefishes,

很不幸， 對洞穴魚而言，

their groundwater habitat

牠們的地下水棲息地，

is also our main source of drinking water.

也是我們主要的飲用水源。

Now, we actually don't know this species' closest relative, yet.

我們其實還不知道 這個物種最近的近親。

It doesn't appear to be anything else in Mexico,

墨西哥找不到任何相像的，

so maybe it's something in Cuba,

所以很可能在古巴、

or Florida, or India.

佛羅里達或印度。

But whatever it is, it might tell us something new about the geology

但不管是什麼，牠都可能告訴我們

加勒比海地質的新發現，

of the Caribbean, or the biology of how to better diagnose

或幫助我們能更正確地 診斷出生物失明的原因。

certain types of blindness.

But I hope we discover this species before it goes extinct too.

但是，我也希望 能在這物種滅絕前找到牠。

And I'm going to spend my one life

身為魚類學者，

as an ichthyologist trying to discover and save

我要窮盡一生的努力， 來發現及拯救

這些不起眼的盲眼小洞穴魚，

these humble little blind cavefishes

that can tell us so much about the geology of the planet

因為牠們能告訴我們非常多 地球的地質知識，

及眼睛、視覺如何演化的生物學。

and the biology of how we see.

Thank you.

謝謝。

(Applause)

（掌聲）