The strange case of the cyclops sheep - Tien Nguyen

翻译人员: Liyu Liu 校对人员: Jenny Yang

In the 1950s, a group of ranchers in Idaho

在上世纪50年代， 爱达荷州的一群牧场工人

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

对新生的畸形小羊而困惑不已。

Mystified by these cyclops sheep,

因为对这些独眼羊感到困惑，

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

他们从美国农业部找来科学家进行调查。

The researchers hypothesized that the pregnant ewes

研究者提出假说，

认为怀孕的母羊吃下了有毒的、 会引起出生缺陷的植物。

had snacked on poisonous birth defect-causing plants.

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

他们采集了当地的植物群， 并将样本喂给实验老鼠，

but struggled to replicate the effect.

但是难以达到相同的效果。

So they decided to directly observe the sheep

因此他们决定直接观察羊群，

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

一位科学家甚至与羊群一起 住了三个夏天。

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

经过十年的试验和错误之后， 科学家终于找到了使羊群畸形的病因：

wild corn lilies.

野生玉米百合。

百合含有一个带六个连接环的活性分子，

The lilies contained an active molecule with six connected rings

that they named cyclopamine in reference to the cyclops sheep.

这被称为环杷明， 以独眼畸形羊命名。

They didn't know exactly how cyclopamine caused the defect

他们并不清楚 环杷明是如何导致缺陷的，

but told ranchers to steer clear.

但告诉牧场工人让羊群避开这种植物。

It took about four decades before a team of biologists,

一个由Philip Beachy领导的 生物学家团队

led by Professor Philip Beachy,

花了大约四十年

stumbled upon the answer.

蹒跚前行寻找答案。

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

他的实验室正在研究一个从许多物种中都发现的一个特定的基因，

from mice to humans,

从老鼠到人类身上都有，

called the hedgehog gene.

叫做hedgehog gene（刺猬蛋白基因）。

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

两位科学家命名了这一基因， 他们随后获得诺贝尔奖。

who found that mutating this gene in fruit flies

他们发现，果蝇体内这一变异的基因

produced pointy spikes like a hedgehog.

会产生像刺猬一样的尖刺。

Beachy and his colleagues performed genetic modifications

Beachy和他的同事通过遗传修饰

to turn off the hedgehog genes in mice.

来关闭老鼠体内的刺猬基因。

This resulted in severe defects in the development

这会导致大脑、器官、眼睛发展的 严重缺陷，

of their brains, organs, and eyes

or, rather, eye.

更确切的说，一只眼睛。

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

在研读一本教科书时， Beachy发现了独眼羊的照片，

and realized what had eluded scientists for four decades.

意识到了迷惑科学家们长达四十年的问题。

Something must have gone awry involving the hedgehog gene.

一些涉及刺猬蛋白基因的东西 一定是出错了。

Let's take a step back.

让我们退回一步看看。

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

基因会告诉细胞做什么和什么时候做的指令，

and they communicate their directives using proteins.

它们运用蛋白质来交流这些指令。

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

刺猬蛋白基因自身会告诉细胞 释放一种所谓的刺猬蛋白，

which kicks off a complex series of cellular signals.

它会开启一系列复杂的细胞信号。

Here's how it works in normal healthy development.

在正常的健康发展状态下， 它是这样工作的。

Hedgehog protein latches on to a protein called patched.

刺猬蛋白锁定在一种叫补丁的蛋白质上。

That inhibits, or holds, patched back,

那会抑制，或者阻止补丁，

allowing another protein called smoothened to freely signal the cells,

让另一种叫smoothened的蛋白 来自由标记细胞，

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

告诉细胞要去往那里， 要成为哪一种组织。

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

以美味的玉米百合的形式而言，

interrupts this pathway by binding onto smoothened.

环杷明通过和smoothened的绑定， 来阻断通路。

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

它锁住了smoothened， 因此让其无法传递信号

needed to mold the brain into two hemispheres,

让大脑形成两个半球

and form fingers or separate eyes.

并形成手指和分开的眼睛。

So even though the hedgehog protein is still doing its job

因此，虽然刺猬蛋白仍在工作，

of keeping the way clear for smoothened,

帮助smoothened保持通路顺畅，

cyclopamine blocks smoothened from passing along its chemical message.

环杷明阻挡了smoothened 通过化学信息传递。

That settled the science behind the one-eyed sheep,

这就解答了独眼羊背后的科学问题，

but Beachy and his team caught the glimmer

但是Beachy和他的团队

从另一个更有益的联系中找到了 一线微光。

of another more beneficial connection.

They noted that uncontrolled activation of the smoothened protein

他们指出，smoothened蛋白质 不受控制的激活

was associated with a human syndrome.

和一种人类综合症相关。

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

它被称作基底细胞痣综合征，

并且它使人们易于患特定的癌症。

The scientists proposed

科学家提出

putting cyclopamine's smoothened binding powers to good use

将环杷明smoothened的捆绑功能

as a treatment for these cancers,

运用到治疗这些癌症上，

as long as the patient wasn't pregnant.

只要病人没有怀孕的话。

Unfortunately, researchers eventually found that cyclopamine

不幸的是，研究者最终发现，

环杷明会导致负面的副作用，

causes negative side effects,

and its chemical properties make it difficult to work with.

并且它的化学性质让人们难以把握。

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

但他们确实发现了与之密切相关的分子 是安全有效的，

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

并且其中两种在2012年和2015年的时候 被批准为皮肤癌药物。

When those farmers first saw the cyclops sheep,

当那些农民第一次见到独眼羊的时候，

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

他们本可以将其记作怪异的基因突变产物 并走开。

Instead, their decision to investigate turned a mystery into medicine

相反，他们做出调查的决定 将这一谜团转变为药物，

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

这展示了有时候 有些事实是眼睛看不到的。