The strange case of the cyclops sheep - Tien Nguyen

譯者: YUYI TONG 審譯者: Helen Chang

在 1950 年代 愛達荷州的一群牧場主

In the 1950s, a group of ranchers in Idaho

were baffled when their sheep gave birth to lambs with a singular deformity.

為他們的羊生下了 奇特變異的小羊而困惑

Mystified by these cyclops sheep,

他們對這些獨眼羊的誕生 感到大惑不解

they called in scientists from the U.S. Department of Agriculture to investigate.

所以請了美國 農業部門的科學家來調查

The researchers hypothesized that the pregnant ewes

研究人員推斷懷孕的母羊

had snacked on poisonous birth defect-causing plants.

吃了會引起先天缺陷的有毒植物

They collected the local flora and fed samples to lab rats,

他們收集了當地的植物樣本 並將它餵給實驗老鼠

but struggled to replicate the effect.

但卻無法重現該種效果

So they decided to directly observe the sheep

所以他們決定直接觀察那些羊

with one scientist even living with the herd for three summers.

其中一名科學家甚至 和羊群同住了三個夏天

After a decade of trial and error, the scientists finally found the culprit,

經過了十年的試錯 科學家們終於找到了罪魁禍首

wild corn lilies.

加州藜蘆

這種植物有著 具六個連接環的活性分子

The lilies contained an active molecule with six connected rings

that they named cyclopamine in reference to the cyclops sheep.

它被稱為「環巴胺」 和獨眼羊息息相關

They didn't know exactly how cyclopamine caused the defect

科學家不知道環巴胺如何造成缺陷

but told ranchers to steer clear.

但也告訴了牧場主 要讓羊群避開它

It took about four decades before a team of biologists,

一群由菲利普·比奇教授 帶領的生物學家花了四十年

led by Professor Philip Beachy,

stumbled upon the answer.

才偶然發現了答案

His lab was studying a specific gene found in many species,

他的實驗室當時正研究一種 許多物種中都能發現的特定基因

from mice to humans,

從小老鼠到人類身上都有

called the hedgehog gene.

該基因稱為「音蝟因子」

It was named by two scientists, who later shared the Noble Prize for their work,

它是由兩位科學家命名的 其後他們還共享了諾貝爾獎

who found that mutating this gene in fruit flies

因為他們發現了 該基因在果蠅身上突變

produced pointy spikes like a hedgehog.

產生了像刺猬一樣尖尖的刺

比奇教授和他的同事通過基因改造

Beachy and his colleagues performed genetic modifications

to turn off the hedgehog genes in mice.

來關閉小老鼠體內的音蝟因子

This resulted in severe defects in the development

這項舉動造成了嚴重的發育缺陷

of their brains, organs, and eyes

影響了牠們的腦部、器官和雙眼

or, rather, eye.

或者說，一隻眼

Then while perusing a textbook, Beachy came across photos of the cyclops sheep

然後比奇教授在細閱教科書時 他看到了獨眼羊的照片

and realized what had eluded scientists for four decades.

並意識到了這個 困惑科學家四十年的答案

Something must have gone awry involving the hedgehog gene.

一定是什麼與音蝟因子 有關的東西出錯了

Let's take a step back.

讓我們回過頭來看看

Genes contain instructions that tell cells what to do and when to do it,

基因裡含有告訴細胞 應該做和何時做什麼的指令

and they communicate their directives using proteins.

而且會使用蛋白質來傳達這些指令

The hedgehog gene itself tells cells to release a so-called hedgehog protein,

音蝟因子會告訴細胞 要釋放所謂的刺猬蛋白

which kicks off a complex series of cellular signals.

而這些蛋白會啟動 一系列複雜的細胞信號

Here's how it works in normal healthy development.

以下是在正常健康發展下的運作情況

刺猬蛋白質會附在 稱為 patched 的蛋白質上

Hedgehog protein latches on to a protein called patched.

That inhibits, or holds, patched back,

抑制或阻止此種蛋白質

allowing another protein called smoothened to freely signal the cells,

從而讓另一種蛋白質 smoothened 自由地向細胞發射信號

telling them where to go and what kind of tissues to become.

告訴細胞要去哪裡 以及要成為怎樣的組織

Cyclopamine, say in the form of a delicious corn lily,

而在美味的加州藜蘆裡存在的環巴胺

interrupts this pathway by binding onto smoothened.

會與 smoothened 結合 來中斷這種連結

That locks smoothened up so that it's unable to send the signals

鎖住此蛋白質，使其無法傳送

needed to mold the brain into two hemispheres,

那些讓大腦塑造成兩個半球

and form fingers or separate eyes.

以及形成手指和兩隻眼睛的信號

So even though the hedgehog protein is still doing its job

所以儘管刺猬蛋白質 仍然在進行它的工作

來為 smoothened 開路

of keeping the way clear for smoothened,

cyclopamine blocks smoothened from passing along its chemical message.

環巴胺會阻止 smoothened 蛋白質傳送化學信息

That settled the science behind the one-eyed sheep,

這就解釋了獨眼羊背後的科學原理

but Beachy and his team caught the glimmer

但是比奇教授和他的團隊還抓住了

of another more beneficial connection.

一個更有用的線索

They noted that uncontrolled activation of the smoothened protein

他們發現 smoothened 蛋白質中不受控的活性

was associated with a human syndrome.

與一種人類的症狀有關

It's known as Basal Cell Nevus Syndrome, and it predisposes people to certain cancers.

這症狀被稱為「基底細胞痣症候群」 會使人們容易患上某些癌症

The scientists proposed

科學家建議

putting cyclopamine's smoothened binding powers to good use

將環巴胺與 smoothened 的結合力

as a treatment for these cancers,

用作這些癌症的治療方法

as long as the patient wasn't pregnant.

只要病人沒有懷孕就可以

Unfortunately, researchers eventually found that cyclopamine

不幸的是，研究人員最終還是發現了

環巴胺會造成的負面副作用

causes negative side effects,

and its chemical properties make it difficult to work with.

而且它的化學性質也使其難以使用

但研究人員的確發現 與其密切相關的分子是安全有效的

But they did discover that closely related molecules are safe and effective,

and two of these drugs were approved in 2012 and 2015 as skin cancer medicines.

而其中兩種藥物也在 2012 和 2015 年獲准成為皮膚癌藥物

When those farmers first saw the cyclops sheep,

當那些牧場工人 第一次看到獨眼羊的時候

they could have chalked it up to a freak genetic mutation and walked away.

他們可以只把那些羊 當成是基因突變而不去管它

Instead, their decision to investigate turned a mystery into medicine

但他們決定去研究 因而讓一個謎團變成了一種藥物

showing that sometimes there's more than meets the eye.

這也顯示出事情有時候 不是表面所見那麼簡單