基因工程與疾病——基因驅動與瘧疾：英語精讀講義

What if you could use genetic engineering to stop humanity's most dangerous predator? 文法

如果你能用基因工程阻止人類最危險的天敵，那會怎樣？

The deadliest animal on the planet responsible for the death of billions,

這個地球上最致命的動物造成了數十億人的死亡，

the mighty mosquito.

它就是強大的蚊子。

Along with other diseases,

除了其他疾病，

it plays host to malaria, 片語搭配

它還是瘧疾的宿主，

one of the cruelest parasites on Earth,

這是地球上最殘酷的寄生蟲之一，

possibly the single biggest killer of humans in history.

甚至可能是歷史上殺死最多人的人類殺手。

In 2015 alone,

僅在 2015 年，

hundreds of millions were infected and almost half a million people died.

就有數億人被感染，近五十萬人死亡。

A new technology could help us eradicate malaria forever.

一項新技術可能幫助我們永遠消滅瘧疾。

But to do so,

但要做到這一點，

we need to engineer a whole animal population.

我們需要改造整個動物族群。

This is not a hypothetical problem.

這不是一個假設性的問題。

The modified mosquitoes already exist in a lab.

經過改造的蚊子已經存在於實驗室中。

Should we use the technology?

我們應該使用這項技術嗎？

And is malaria bad enough to risk it? 文法

瘧疾是否嚴重到值得我們去冒險？

Malaria is caused by a group of microorganisms,

瘧疾是由一組微生物引起的，

Plasmodia.

即瘧原蟲 (Plasmodia)。

Very weird microorganisms that consist of just a single cell.

這是非常奇怪的微生物，僅由單細胞組成。

They're parasites that completely rely on mosquitoes. 片語搭配

它們是完全依賴蚊子的寄生蟲。

Malaria always starts with an insect bite.

瘧疾總是從被蚊蟲叮咬開始的。

In its salivary glands,

在其唾液腺中，

thousands of sporozoites wait until the insect penetrates your skin.

成千上萬的子孢子等待著，直到這隻昆蟲刺穿你的皮膚。

Immediately after invading you,

在侵入你體內後，

they head for the liver, 片語動詞

它們立即前往肝臟，

where they quietly enter big cells and hide from the immune system.

在那裡它們悄悄進入大細胞並躲避免疫系統。

For up to a month,

在長達一個月的時間裡，

they stay here in stealth mode,

它們在這裡保持潛伏模式，

consuming the cells alive and changing into their next form,

活生生地吞噬細胞並變成它們的下一個形態，

small drop-like merozoites.

小水滴狀的裂殖子。

They multiply,

它們開始繁殖，

generating thousands of themselves and then burst out of the cells. 片語動詞

生成數千個自身的複製體，然後突破細胞而出。

So thousands of parasites head into the bloodstream to look for their next victims,

於是，成千上萬的寄生蟲進入血液尋找它們的下一個目標，

red blood cells.

即紅血球。

To stay unnoticed,

為了不被發現，

they wrap themselves in the membranes of the cells they killed.

它們用被自己殺死的細胞的細胞膜把自己包裹起來。

Imagine that.

想像一下。

Killing someone from the inside and then taking their skin as camouflage.

從內部殺死某人，然後拿他們的皮膚當作偽裝。

Brutal.

實在殘忍。

They now violently attack red blood cells,

現在，它們瘋狂攻擊紅血球，

multiplying inside them until they burst,

在紅血球內繁殖直到細胞破裂，

then finding more red blood cells,

然後尋找更多的紅血球，

and this cycle repeats over and over. 片語搭配

這個循環一遍又一遍地重複。

Pieces of dead cells spread lots of toxic waste material,

死亡細胞的碎片散佈出大量有毒廢物，

which activates a powerful immune response,

這會活化強烈的免疫反應，

causing flu-like symptoms. 用詞

引起類似流感的症狀。

Among the symptoms are high fever,

症狀包括高燒、

sweats and chills,

盜汗和發冷、

convulsions, headaches,

抽搐、頭痛，

and sometimes vomiting and diarrhea.

有時還有嘔吐和腹瀉。

If malaria breaches the blood-brain barrier, 用詞

如果瘧疾突破了血腦屏障，

it can cause coma,

可能會導致昏迷、

neurological damage,

神經損傷，

or death.

甚至死亡。

The parasites are ready for evacuation now.

寄生蟲現在準備好撤離了。

When another mosquito bites the infected human,

當另一隻蚊子叮咬了受感染的人時，

they get a ride. 慣用語

它們便搭上了順風車。

The cycle can start over.

循環又可以重新開始了。

In 2015,

2015 年，

the Zika virus,

茲卡 (Zika) 病毒——

which causes horrible birth defects if it infects pregnant women,

如果感染孕婦會導致可怕的先天性缺陷——

spread rapidly into new areas around the globe.

迅速蔓延到全球的新地區。

It too is carried by a mosquito.

它也是由蚊子攜帶的。

The mosquito is the perfect carrier for human diseases.

蚊子是人類疾病的完美載體。

They've been around for at least 200 million years.

它們已經存在了至少兩億年。

There are trillions of them,

它們的數量數以兆計，

and a single one can lay up to 300 eggs at a time. 片語搭配

且單隻蚊子一次就能產下多達 300 顆卵。

They are practically impossible to eradicate

它們幾乎是不可能被根除的，

and the perfect parasite taxi. 慣用語

是完美的「寄生蟲計程車」。

But today,

但今天，

we have a new revolutionary technology that could enable us to finally win the war against them. 慣用語

我們擁有了一項新的革命性技術，或許能讓我們最終贏得與它們的戰爭。

CRISPR.

也就是 CRISPR。

For the first time in human history, 片語搭配

在人類歷史上，我們第一次

we have the tools to make fast,

擁有了可以快速、

large-scale changes to entire species,

大規模改變整個物種的工具，

changing their genetic information as we please. 片語搭配

能隨心所欲地改變它們的遺傳資訊。

So, instead of attacking isolated groups of insects, 文法

那麼，與其攻擊孤立的昆蟲群體，

why not just change the types that transmit diseases? 語氣意圖

為什麼不直接改變傳播疾病的種類呢？

Using genetic engineering,

科學家們利用基因工程，

scientists successfully created a strain of mosquitoes that are immune to the malaria parasite 片語搭配

成功創造出了一種對瘧原蟲免疫的蚊子品種，

by adding a new antibody gene that specifically targets Plasmodium.

做法是添加一種專門靶向瘧原蟲的新抗體基因。

These mosquitoes will never spread malaria.

這些蚊子將永遠不會傳播瘧疾。

But just changing genetic information is not enough. 文法

但僅僅改變遺傳資訊是不夠的。

The edits would only be inherited by half the offspring

這種編輯只會被一半的後代遺傳，

because most genes have two versions inside the genome as a failsafe. 用詞

因為大多數基因在基因組內有兩個版本，作為一種安全機制。

So, after just two generations,

所以，僅僅過了兩代之後，

at most only half of the offspring would carry the engineered gene.

最多只有一半的後代會攜帶這種經過設計的基因。

In a population of billions of mosquitoes,

在數十億隻蚊子的族群中，

they would hardly make a difference. 片語搭配

它們幾乎不會產生什麼影響。

A genetic engineering method called the gene drive solves this problem. 文化背景

一種被稱為基因驅動 (gene drive) 的基因工程方法解決了這個問題。

It forces the new gene to become dominant in the following generations,

它迫使新基因在後代中成為顯性，

overpowering the old gene almost completely.

幾乎完全壓倒了舊基因。

Thanks to this twist, 表達脈絡

多虧了這個巧妙的機制，

99.5% of all the engineered mosquitoes offspring

在所有經過基因改造的蚊子後代中，99.5% 的個體

will carry the anti-malaria edit.

將攜帶抗瘧疾的編輯基因。

If we were to release enough engineered mosquitoes into the wild 文法

如果我們在野外釋放足夠多的基因改造蚊子，

to mate with normal mosquitoes,

讓它們與正常蚊子交配，

the malaria-blocking genes would spread extremely quickly.

阻斷瘧疾的基因就會極其迅速地傳播。

As the new gene becomes a permanent feature of the mosquito population,

隨著新基因成為蚊子族群的永久特徵，

Plasmodium would lose its home base. 慣用語

瘧原蟲將失去它的大本營。

Scientists hope that the change would be so fast 文法

科學家們希望這種變化會非常快，

that they could not adapt to it quickly enough.

快到它們無法及時適應。

Malaria could virtually disappear.

瘧疾可能就會真正銷聲匿跡。

If you take into account that maybe half a million children are killed by it every year, 片語搭配

如果你考慮到每年可能有 50 萬名兒童死於這種疾病，

about five have died since this video started,

自本影片開始以來，大約已有五個孩子死去了，

some scientists argue that we should use the technology sooner rather than later. 慣用語

一些科學家認為，我們應該盡早使用這項技術。

The mosquitoes themselves would probably only profit from this.

蚊子本身大概也能從中獲益。

They don't have anything to gain from carrying parasites. 片語搭配

攜帶寄生蟲對它們沒有任何好處。

And this might only be the first step.

這也許僅僅是第一步。

Malaria might just be the beginning.

瘧疾可能只是個開始。

Different mosquitoes also carry dengue fever and Zika.

不同的蚊子還攜帶登革熱和茲卡病毒。

Ticks transmit Lyme disease.

蜱蟲傳播萊姆病。

Flies transmit sleeping sickness.

蒼蠅傳播非洲睡眠症。

Fleas transmit the plague.

跳蚤傳播鼠疫。

We could save millions of lives and prevent suffering on an unbelievable scale.

我們可以拯救數百萬人的生命，並防止難以想像的苦難。

So, why haven't we done this yet? 表達脈絡

那麼，為什麼我們還沒有這麼做呢？

For one, CRISPR editing is barely four years old. 講解

首先，CRISPR 編輯技術面世還不到四年。

So, until very recently,

所以直到最近，

we just couldn't do it as fast and easily.

我們還無法如此快速、輕鬆地進行這種操作。

And there are valid concerns.

而且人們有合理的擔憂。

Never before have humans consciously changed the genetic code of a free-living organism on this scale. 文法

人類以前從未在這個規模上有意識地改變過一種自由生存生物的遺傳密碼。

Once we do it, there is no going back. 慣用語

一旦我們這麼做了，就沒有回頭路了。

So, it has to be done right

因此，必須謹慎行事，

because there could be unwanted consequences if we set out to edit nature. 片語動詞

因為如果我們著手編輯自然，可能會產生意想不到的後果。

In the specific case of malaria, though, 表達脈絡

不過，在瘧疾的具體案例中，

the risk might be acceptable since the genetic modification doesn't make a big change in the overall genome.

風險也許是可以接受的，因為這種基因改造不會對整個基因組造成重大改變。

It only changes a very specific part.

它只改變了一個非常特定的部分。

The worst-case scenario here is probably that it might not work 片語搭配

這裡最糟糕的情況，大概就是它可能不起作用，

or that the parasite adapts in a negative way.

或者寄生蟲以一種負面的方式去適應它。

There is still much debate.

爭論仍在繼續。

Technology as powerful as gene drive needs to be handled with a lot of care. 講解

像基因驅動這樣強大的技術，需要非常謹慎地處理。

But at some point,

但在某些時候，

we have to ask ourselves, 片語搭配

我們必須問自己，

is it unethical to not use this technology

當每天有 1,000 名兒童死亡時，

when every day 1,000 children die?

不使用這項技術是否才是不道德的？

Humanity has to decide how to act on this in the next few years. 片語動詞

人類必須決定在未來幾年內如何應對這一問題。

The public discussion is way behind the technology in this case. 用詞

在這個案例中，公眾的討論遠遠落後於技術的發展。

What do you think?

你怎麼看？

This video was made possible in part by viewer donations on Patreon. 片語搭配

本影片的部分製作經費來源於觀眾在 Patreon 上的捐款。

If you want to help us make more videos like this and get nice rewards in return, 片語搭配

如果你想幫助我們製作更多類似的影片並獲得豐厚的回報，

you can do so here.

你可以在這裡贊助。

We really appreciate it.

我們非常感謝。

If you want to learn more about the topic of genetic engineering,

如果你想了解更多關於基因工程的話題，

we have another video about CRISPR and GMOs.

我們還有另一個關於 CRISPR 和基因改造生物 (GMOs) 的影片。

And in case that's too much biology for you, 文法

如果這對你來說生物學知識太多了，

here's a space playlist.

這裡有一個關於太空的播放清單。