But one myth in particular just won't go away.

但有一個神話特別是不會消失。

That SARS cov to the virus that causes Covid 19 isn't naturally occurring and was actually man made.

那個SARS cov到導致Covid 19的病毒不是自然產生的，其實是人為的。

In fact, one substantial survey found that almost 30% of Americans believe that this virus came from a lab.

事實上，一項實質性的調查發現，近30%的美國人認為這種病毒來自實驗室。

But scientists believe that they can confidently say that the virus wasn't created by humans, and the myth going around is nothing more than that.

但科學家認為，他們可以自信地說，這種病毒不是人類製造的，流傳的神話也不過如此。

A myth.

一個神話。

So how do they know with such certainty?

那麼，他們是如何如此肯定地知道的呢？

The key is in the virus's genetic code?

關鍵是在病毒的遺傳密碼中？

This is the genomic sequence for SARS Cov two.

這是SARS Cov two的基因組序列。

It was decoded in January 2020 just weeks after the world started to learn of this novel coronavirus.

它在2020年1月被解碼，就在世界開始瞭解這種新型冠狀病毒的幾周後。

Each of those letters is a genetic building blocks known as a nucleotide, and when built up, they form an organism's genetic code, which we can use to understand them.

這些字母中的每一個都是被稱為核苷酸的基因構件，當它們建立起來後，就形成了生物體的遺傳密碼，我們可以用它來了解它們。

Each organism has a different code and a varying amount of nucleotides.

每個生物體的代碼不同，核苷酸的數量也不同。

A human has about three billion of them, whereas a virus such as SARS COV two has about 30,000.

一個人大約有30億個，而像SARS COV two這樣的病毒大約有3萬個。

Your genetic sequence can give information about your hair, eye color, sex and lineage.

你的基因序列可以提供關於你的頭髮、眼睛顏色、性別和血統的資訊。

And just like your jeans give clues about who and where you come from.

就像你的牛仔褲一樣，給了你從哪裡來的線索。

Scientists can use a virus genome sequence to help explain where that virus originated as well.

科學家也可以利用病毒基因組序列來幫助解釋該病毒的來源。

An ancestry test for viruses, if you will.

如果你願意的話，可以做一個病毒的祖先測試。

We hummed in on the parts of the virus that we thought were unique, and it might play a role in the evolution of the virus, but also in the pathogenesis of it.

我們哼了一聲，我們認為病毒的部分是獨特的，它可能在病毒的進化中起到了作用，也可能在病毒的發病過程中起到了作用。

And a couple of things stood out pretty quickly when we started to compare with the other Corona viruses that have come before.

而當我們開始與之前的其他電暈病毒進行比較時，有幾件事很快就脫穎而出。

That's Robert Garry, a professor of microbiology and immunology at Tulane University.

這是羅伯特-加里，杜蘭大學微生物學和免疫學教授。

Along with his colleagues, he used the virus sequence to try and understand where SARS cov two came from.

他和同事一起，利用病毒序列試圖瞭解SARS cov two的來源。

They first looked at the virus's backbone.

他們首先查看了病毒的主幹。

That's the whole genomic structure unique to each virus.

這就是每個病毒獨有的整個基因組結構。

Like a viral template simplified the backbone for SARS cov two, and it's 30,000 nucleotide looks a little bit like this.

像病毒模板簡化了SARS cov two的骨架，它的3萬個核苷酸看起來有點像這樣。

Each section is responsible for a part of the virus.

每個部分都負責病毒的一部分。

For example, this one is responsible for the spike proteins you may have seen lining the virus shell, so it may not come as a surprise that to engineer a virus in a lab you would need to start with a backbone.

例如，這個負責你可能已經看到的病毒外殼內襯的尖峰蛋白，是以，在實驗室中設計病毒，你需要從骨幹開始，這可能並不奇怪。

But to manufacture from scratch the backbone of a virus that can also cause disease is almost impossible.

但要從頭開始製造出同樣可以致病的病毒骨幹，幾乎是不可能的。

I mean, people just don't know enough about what makes the virus pathogenic to be able to symbol that.

我的意思是，人們只是對病毒的致病原因不夠了解，不能象徵著。

How do you pick amongst all the possibilities to get to that last little bit?

你如何在所有的可能性中挑選出最後一點？

That's going to turn it into this world wide pathogen?

那就要把它變成這個世界性的病原體？

Which sequences do you think about to put in there?

你想到哪些序列放進去？

Simply?

簡單的？

There is just not enough knowledge about how to make a new virus that would also cause significant devastation.

只是對如何製造一種新的病毒，也會造成重大的破壞性的知識不夠。

Like SARS.

就像SARS。

COV two has so creating a new deadly backbone is pretty much impossible.

COV二有所以創造一個新的致命骨幹是非常不可能的。

But there is another way.

但還有另一種方法。

The novel coronavirus could have been created in a lab and that would be using an existing virus backbone or genetic sequence as a starting point with a recycled backbone.

新型冠狀病毒可以在實驗室中創建，那就是以現有的病毒骨幹或基因序列為起點，回收骨幹。

Two main methods could have been used to create the new virus.

有兩種主要方法可以用來製造新病毒。

They could have either quickly mutated it or added and deleted parts of the existing virus.

他們可以迅速將其變異，也可以在現有病毒中增加和刪除部分內容。

But additions and deletions and a virus leave a trace that can be pointed out pretty quickly, a little bit like removing a red brick from a wall and replacing it with a black brick.

但增刪和病毒留下的痕跡，很快就能指出來，有點像把牆上的一塊紅磚拆掉，換上一塊黑磚。

This is exactly what Macek Bony, an associate professor at Penn State, looked for.

這正是賓夕法尼亞州立大學副教授Macek Bony所尋找的。

You might see an insertion that looks unusual, and you look out in nature and you see that no other viruses have genetic insertions like that.

你可能會看到一個看起來不尋常的插入，你在自然界中看一看，你會發現其他病毒都沒有這樣的基因插入。

We did not see any genetic insertions that not also identified in nature, so there's no evidence suggesting that it was man made or laboratory created somehow.

我們沒有看到任何沒有在自然界中被識別的基因插入，所以沒有證據表明它是人為的或實驗室以某種方式創造的。

So what if they went with the other option and mutated an existing virus?

那如果他們選擇了另一種方案，把現有的病毒變異了呢？

This is known as serial passage and acts in a similar way to selective breeding.

這就是所謂的連續通過，其作用與選擇性育種類似。

Scientists are able to mimic evolution to a degree by forcing the virus to mutate over and over again into a potentially different form.

科學家能夠在一定程度上模仿進化，迫使病毒反覆變異，變成一種潛在的不同形式。

This can be used to weaken a virus, which is how some vaccines have been made, or to strengthen a virus, say, by making it more transmissible.

這可以用來削弱病毒，這就是一些疫苗的製作方法，也可以用來加強病毒，比如說，使其更具傳播性。

But for this to work, the existing virus would have to show significant genetic similarity to the new virus.

但要想成功，現有的病毒必須顯示出與新病毒在基因上的顯著相似性。

In fact, they would have to be almost identical because this process only speeds up viral evolution and has a limit.

事實上，它們必須幾乎完全相同，因為這個過程只會加快病毒進化的速度，而且有一個極限。

It's not possible to direct mutations into a completely different form.

不可能引導突變成完全不同的形式。

Yet Gary and his team found that the backbone for SARS cov two was strictly unique, differing significantly from other Corona viruses.

然而Gary和他的團隊發現，SARS cov two的骨幹嚴格來說是獨一無二的，與其他Corona病毒有很大區別。

For example, SARS cov the first Stars has only about a 79% genetic sequence match to SARS cov two.

例如，SARS cov the first Stars與SARS cov two的基因序列匹配度只有79%左右。

So it's ruled out the best candidate is R 80 g 13, a bat coronavirus with a 96% gene sequence.

所以排除了最佳的候選者是R 80 g 13，這是一種基因序列為96%的蝙蝠冠狀病毒。

Similarity 96% sounds pretty close, but in genetic terms, that's actually pretty long ways away.

相似度96%，聽起來很接近，但從遺傳學的角度來說，其實距離很遠。

To put it in perspective, humans and chimpanzees share 99% of the same genome, and you may have noticed there's still a large difference between the two for SARS cov two and R 80 g 13.

說句題外話，人類和黑猩猩有99%的基因組是一樣的，你可能已經注意到了SARS cov two和R 80 g 13兩者之間還是有很大的區別。

That 4% is the difference of about 800 nucleotides, or about 50 years of natural evolution.

這4%就是大約800個核苷酸的差別，也就是大約50年的自然進化。

800 is too big a barrier.

800元是一個太大的障礙。

You had something that was 99.5% or 99.7% similar.

你的東西有99.5%或99.7%的相似度。

Maybe only 20 or 30 nucleotides, you might get away with it.

也許只有20或30個核苷酸，你可能會逃脫它。

You might be able to manufacture that doing the lab, but it just wouldn't be possible with current knowledge and existing viruses.

你也許能製造出做實驗室的，但以目前的知識和現有的病毒來說，就是不可能。

There's also another part of the gene sequence that helped Gary and his colleagues learn about the natural origins of sars-cov-2, in particular this set of nucleotides in the gene sequence.

還有一部分基因序列幫助Gary和他的同事們瞭解了sars-cov-2的自然起源，特別是基因序列中的這組核苷酸。

You might remember those from earlier they're responsible for the virus spike proteins.

你可能還記得之前的那些，他們負責病毒尖峰蛋白。

The pointy claw like arms lining the outside of the virus that give it its distinctive appearance and coronavirus is their name.

病毒外側的尖爪一樣的手臂，讓它有了獨特的外觀，冠狀病毒就是它們的名字。

Specific viruses, including coronavirus, is use these arms to enter and take over host cells.

特定的病毒，包括冠狀病毒，是利用這些手臂進入並接管宿主細胞。

But this piece of the spike protein help tell the researchers that this virus originated in nature.

但這塊尖峰蛋白有助於告訴研究人員，這種病毒來源於自然界。

This set of nucleotides relates to the receptor binding domain, or RBD.

這組核苷酸與受體結合域，或RBD有關。

That's the part that latches onto the receptors on targeted cells as viruses can only survive when inside other cells.

那是吸附在目標細胞上的受體的部分，因為病毒只有在其他細胞內才能生存。

This is a vital section that you would have to focus on if you were to make a virus in a lab, Gary and his team found.

這是一個至關重要的部分，如果你要在實驗室裡製造病毒，加里和他的團隊發現。

The RBD has evolved specifically to bind to the human cell a C to a receptor usually used to help regulate blood pressure, but it's the way it's so successfully binds to the A C two receptor that is crucial.

RBD已經進化到專門與人體細胞a C到受體結合，通常用於幫助調節血壓，但它如此成功地與a C兩個受體結合的方式是至關重要的。

You see, when a scientist tests what aspects would make a virus more potent, they run models through computer simulations.

你看，當科學家測試哪些方面會使病毒更有效時，他們會通過計算機模擬運行模型。

But when researchers put this sequence through those simulations, they found that sars-cov-2 RBD shouldn't be successful at all.

但當研究人員將這個序列通過這些模擬時，他們發現sars-cov-2 RBD應該根本不會成功。

And what actually caused poor efficiency and transmission, which we know is not the case by working in the lab, working with computer, trying to figure it out.

而實際上是什麼原因造成了效率和傳輸不暢，我們通過在實驗室工作，用電腦工作，想辦法解決，就知道不是這樣的。

I mean, they just would not have come up with this particular way to have this virus buying this receptor a very important part of the whole replication process.

我的意思是，他們只是不會想出這種特殊的方式來讓這種病毒購買這種受體，這是整個複製過程中非常重要的一部分。

In other words, if your goal was to make a virus to infect humans, you wouldn't have chosen this one.

換句話說，如果你的目標是製造一種感染人類的病毒，你就不會選擇這個。

Basically, what nature has been has come up with a solution for binding that is better than any computer and ultimately better than what any scientists could come up with.

基本上，自然界一直以來都在想辦法解決綁定的問題，比任何計算機都要好，最終也比任何科學家能想出的辦法都要好。

So we know why.

所以我們知道原因了。

Scientists confidently say Sars-cov-2 wasn't made in a lab.

科學家自信地說，Sars-cov-2不是在實驗室裡製造的。

But that's not the end of the story.

但這不是故事的結尾。

It's also been rumored that Sars-cov-2 was a known virus that was accidentally leaked from a lab now we can't say for certain this isn't the case, but it's highly unlikely.

也有傳言說，Sars-cov-2是一種已知的病毒，是不小心從實驗室裡洩露出來的，現在我們不能確定這是不是真的，但這是極不可能的。

For one, this virus wasn't sequenced before January 2020.

其一，這種病毒在2020年1月之前沒有測序。

And if it was, the world would know because the Wuhan Institute of Virology was specifically looking for something like this.

如果是的話，全世界都會知道，因為武漢病毒學研究所專門尋找這樣的東西。

In order to protect the world from any outbreaks, they would have come up with the SARS coronavirus.

為了保護世界不受疫情影響，他們會想出SARS冠狀病毒。

That was 76% similar to the original stars.

這與原來的明星相似度高達76%。

One, I mean, they would have published that as fast as they could.

一，我的意思是，他們會以最快的速度發表。

That would have been, at least in the scientific world, very big news.

至少在科學界，這將是一個非常大的新聞。

But it's also just statistically highly unlikely.

但這也只是統計學上的極不可能。

So just that in nature, there literally beings of people that are having millions of encounters with these animals.

所以就在自然界中，真的有眾生與這些動物有千萬次的接觸。

And, you know, we're talking about a handful.

而且，你知道，我們說的是少數。

A few dozen made in the whole world of scientists that go out and trap that.

在整個世界的科學家中，有幾十位做了出去，困住了那。

So just on the odds of the things, that's just a minuscule chance that it was just one scientists that accidentally better themselves.

所以就在事情的機率上，這只是一個微乎其微的機率，只是一個科學家不小心把自己搞好了。

And that's very sophisticated laboratory setting.

而這是非常複雜的實驗室環境。

So Sars-cov-2, whose origin is no longer a mystery but where and how it jumped in nature.

所以，Sars-cov-2，它的起源已經不是一個謎，而是它在自然界的哪裡和如何跳躍。

Well, that's a question many are still trying to answer.

嗯，這個問題很多人還在嘗試回答。

Mhm.

嗯