MyOOPS開放式課程
請加入會員以使用更多個人化功能
來自全球頂尖大學的開放式課程,現在由世界各國的數千名義工志工為您翻譯成中文。請免費享用!
課程來源:TED
     

 

Jack Horner 談由雞造出一隻恐龍

Jack Horner: Building a dinosaur from a chicken

 

講者:Jack Horner

2011年3月演講,2011年6月在TED2011上線

 

翻譯:洪曉慧

編輯:朱學恆

簡繁轉換:洪曉慧

後製:洪曉慧

字幕影片後制:謝旻均

 

影片請按此下載

MAC及手持裝置版本請按此下載

閱讀中文字幕純文字版本

 

關於這場演講

著名古生物學家Jack Horner的職業生涯致力於嘗試重新製造一隻恐龍。他發現的化石具有保存相當完整的血管和軟組織,但從未發現完整的DNA。因此,以一種新方法,他採用現存於世的恐龍後裔(雞),對牠們進行基因工程,來重新活化牠們祖先的特徵-包括牙齒、尾巴,甚至前肢-以製造一隻「雞恐龍」。

 

關於Jack Horner

Jack Horner和他的挖掘團隊所首次發現的證據包含了:恐龍是由父母照顧、具有廣泛棲息地、及恐龍是群體動物,還有世界上第一個恐龍胚胎。

 

為什麼要聽他演講

(無資料網頁)

 

Jack Horner的英語網上資料

(無資料網頁)

 

[TED科技‧娛樂‧設計]

已有中譯字幕的TED影片目錄(繁體)(簡體)。請注意繁簡目錄是不一樣的。

 

Jack Horner 談由雞造出一隻恐龍

當我在蒙大拿州長大時,我有兩個夢想:我想成為一名古生物學家,恐龍古生物學家,我希望有隻寵物恐龍,所以這是我一生一直努力的目標。我職業生涯的初期就很幸運,我找東西的運氣很好。我不是很善於閱讀,事實上很多東西我都讀不懂,我有嚴重的閱讀困難,所以閱讀是對我來說是最困難的事。相反的,我出去找東西,然後就只是將東西揀起來,基本上我實行的方式是在大街上找錢。(笑聲)我在山上四處尋找,發現了一些東西。

 

我很幸運找到了一些東西,像是西半球第一顆恐龍蛋,第一個在巢中的幼恐龍,第一個恐龍胚胎,以及成堆的骨頭。當時正好是人們剛剛開始瞭解,恐龍不是人們多年來認為的那種大而愚蠢的綠色爬行動物,人們開始知道恐龍是特別的。

 

因此,在那個時候,我能跟我的同事一起提出一些有趣的假說。基於我們擁有的證據,我們能確實說-恐龍會築巢且進行群體生活,照顧牠們的幼恐龍,將食物帶回給幼恐龍,並以龐大的群體進行遷徙活動。所以這是非常有趣的東西,我一直不斷尋找更多相關情況,並發現恐龍確實非常具有社會性。我們已經找到了很多證據,說明恐龍從青年期到成年期會發生改變。牠們的外觀會有所不同,這是所有社會性動物都有的特徵。社會群體中的動物,青年期與成年期看起來總是不同,成年者可以識別出未成年者,未成年者可以識別出成年者。因此,我們正在製作更好的圖片,來模擬恐龍的模樣。牠們不是只會追逐吉普車。

 

(笑聲)

 

我想吸引Michael Crichton(侏羅紀公園作者)的正是牠們的社會性,他在書中談到了這個社會性動物。當然,史蒂芬史匹柏描繪這些恐龍是非常社會化的動物。這個故事的主題是培育出一隻恐龍,所以我們談到《侏羅紀公園》的部份。Michael Crichton確實是第一位提到使恐龍起死回生的人,大家都知道這個故事,對吧?我的意思是,我假設在場各位都看過《侏羅紀公園》。

 

如果你想培育出一隻恐龍,你到野外去,為自己找一塊石化的樹汁,也就是一般所知的琥珀,有一些吸血昆蟲在裡面,保存的很完整,你將昆蟲取出,鑽進它的身體,吸出一些DNA,因為很顯然當時所有昆蟲都吸了一些血,吸了恐龍的DNA。你將DNA帶回實驗室做基因複製,我猜你可能把它注入鴕鳥蛋中,或類似的東西,然後,你等著,然後,你瞧,冒出一隻小恐龍寶寶,每個人都滿心歡喜。(笑聲)他們開心了一次又一次,他們繼續這麼做,他們不斷製造這些東西,然後,然後,然後,然後…這些恐龍會形成一個社群,展現牠們的社會化行為。牠們聚在一起,牠們共謀,當然,這造就了史蒂芬史匹柏的電影,充滿陰謀的恐龍四處追逐人類。

 

所以,我想大家都知道,如果你確實擁有一塊琥珀,裡面有一隻昆蟲,你鑽了進去,從昆蟲中取出一些東西,你將它進行基因複製,你一遍又一遍地這麼做,你會有一個滿是蚊子的房間。(笑聲)。(掌聲)。也可能是一大堆樹木。

 

現在,如果你想要恐龍的DNA,我會說,那就去找恐龍吧!所以這就是我們所做的。回到1993年電影上映時,我們事實上得到美國國家科學基金會同意,嘗試從一隻恐龍中提取DNA。我們選擇了左邊這隻恐龍,一隻暴龍,這是一個非常好的標本,我以前的一個博士生,Mary Schweitzer博士,她確實具有進行這類工作的知識背景。她看著這隻暴龍的骨頭,其中一隻大腿骨,她發現那裡有一些非常有趣的結構,他們發現這些紅色的圓形物體,無論怎麼看都像紅血球細胞,它們位於看似穿過骨頭的血管中。因此她想,好,這是怎麼回事啊?於是,她從中採樣了一些物質,它不是DNA,她沒有發現DNA,但她確實發現血紅素,這是血紅蛋白的生物基礎成分。這真的很酷、很有趣,這是-我們得到有6500萬年歷史的血紅素,我們試了又試,卻無法真正從中取得任何其他東西。

 

幾年過去了,然後我們開始了地獄溪計畫。地獄溪計畫是一個大工程,我們希望盡可能獲得我們能發現的恐龍,並希望找到一些含有更多物質的恐龍。在東蒙大拿州還有很多場所,很多荒地,而且人不是很多,所以你可以去那裡找到很多東西。我們確實發現了很多東西,我們發現了很多暴龍,但我們發現一隻特殊的暴龍,我們叫牠B - REX。B–REX在一千立方碼的岩石下被發現,牠不是一隻很完整的暴龍,不是一隻非常大的暴龍,但牠是一隻非常特殊的B - REX。我和我的同事們將牠解剖,藉由檢查限制生長的紋路,一些在裡面紋路,我們能夠確定B-rex在16歲去世。我們並不真的知道恐龍能活多久,因為我們還沒發現最老的恐龍,但這隻在16歲去世。

 

我們將樣本給Mary Schweitzer,她事實上能確定B - REX是母的,基於在骨骼裡發現的髓組織。髓組織是由鈣積聚而成,基本上就是當動物或鳥類懷孕時鈣的儲存量。這是鳥類和恐龍的髓組織關連圖。但Mary做了更進一步研究,她將骨骼浸入酸中。現在我們都知道,這骨頭是化石,所以如果你將它浸入酸中,應該什麼都不會留下,但有些東西殘留下來了。血管殘留下來了,這是柔軟、透明的血管,所以這是第一個來自恐龍的軟組織。這相當驚人。但她也發現了骨細胞,就是建構骨骼的細胞。經過一再嘗試,我們無法找到DNA,但她確實找到蛋白質的證據。

 

但我們想,也許,嗯,我們想,也許這些物質在出土後分解掉了。我們想,也許它分解的速度非常快。因此,我們在輪拖車後方建立了一個實驗室,實際將實驗室搬到野外,以便能得到更好的樣本。我們確實得到了,我們得到了更好的材料。這些細胞看起來更好,血管也是,還有膠原蛋白。我的意思是,它們是很棒的東西,但不是恐龍的DNA。因此,我們發現恐龍的DNA和所有的DNA分解速度都過快了,我們無法達成像他們在《侏羅紀公園》做的事,我們無法以一隻恐龍來造出另一隻恐龍。

 

但鳥類也是恐龍,鳥類是活生生的恐龍,我們事實上將牠們分類為恐龍,我們現在將這兩種動物稱為非鳥類恐龍及鳥類恐龍。因此,非鳥類恐龍就是那些已滅絕的龐大笨重恐龍,鳥類恐龍就是我們現代的鳥類。因此,我們不需要製造恐龍,因為我們已經有了。

 

(笑聲)

 

我知道,你們就像六年級學生一樣壞。(笑聲)。六年級學生看著牠說,「才不呢!」。(笑聲)。「你可以叫牠恐龍,但看看迅猛龍:迅猛龍很酷。」。(笑聲)。「雞不酷。」。(笑聲)。因此,你們可以想像,這就是我們的問題。雞是恐龍,我是說真的,你無法爭辯這一點,因為分類者和我們已這麼分類了。(笑聲)。(掌聲)。但六年級學生要求,「改造雞吧!」。(笑聲)。所以這就是我要在這裡向大家介紹的,我們將如何改造雞。

 

因此,我們有幾種方法,我們事實上可以改造雞,因為演化的作用,我們事實上有一些演化工具,我們稱之為生物改造工具,我們選擇性的進行,我們知道選擇是可行的方法。我們從似狼的動物開始,我們最後選了一隻馬爾濟斯。我的意思,這是-這確實是基因改造,或任何外觀逗趣的小狗,我們也可以用基因轉殖來做。基因轉殖確實也很酷,就是你從一隻動物身上取出一個基因,將它接到另一隻動物身上,這就是人們製造螢光魚的方法。你從珊瑚或水母身上取出發光基因,將它接在一隻斑馬魚身上,然後噗的一聲,牠們發光了。這非常酷,人們顯然從牠們身上賺了不少錢,現在他們正在做螢光兔和各種發光的東西,我想我們可以做一隻螢光雞。(笑聲)。但我不認為這能滿足六年級學生。

 

但還有另一件事,就是我們所謂的活化返祖現象。活化返祖現象基本上是-返祖現象是指祖先的特徵,你們聽說過,偶爾孩子出生時會有尾巴,因為這是一個祖先的特徵,因此可能發生幾種返祖現象;蛇偶爾生下來會有腿,以下是一個例子。這是一隻有牙齒的雞,在Madison的威斯康辛大學,一個名叫Matthew Harris的人想出一個辦法,來刺激牙齒的基因,所以能真正轉變牙齒的基因,而讓雞長牙。這是一個很棒的特徵,我們可以保留這一點,我們知道可以使用這個技術,可以使雞長牙,這越來越接近我們的目標了,比螢光雞更好。

 

(笑聲)

 

我的一位朋友,一位同事,McGill大學的Hans Larsson博士,事實上是研究返祖現象的,他藉由觀察鳥類的胚胎形成來研究這一點,實際觀察牠們如何發育。他對鳥類如何失去尾巴感興趣,他也對前肢、手轉變成翅膀感興趣,他也正在尋找這些基因。我說:「好吧,如果你能找到這些,我就可以轉變它們,並做出我需要為六年級學生做的東西。」因此他同意了,所以這就是我們正在尋找的東西。

 

如果你看恐龍的前肢,迅猛龍有很酷的、長著爪子的前肢。始祖鳥,這是一種鳥,一種原始的鳥,仍然有非常原始的前肢,但如你所見,鴿子、雞、或另一種其他鳥類,有一種看起來很怪的前肢,因為這前肢是一副翅膀。但很酷的事情是,如果你觀察胚胎,發育中的胚胎,這樣的前肢事實上看起來幾乎像始祖鳥的前肢,它有三根手指,三根趾頭,但一個基因啟動,將它們融合在一起,所以我們要找的就是那個基因。我們希望阻止那個基因啟動,停止將這些前肢融合在一起,所以我們可以讓一隻雞孵化出來時擁有三根手指,就像始祖鳥一樣。尾巴也是同樣情形。鳥類尾巴基本上是未發育完全的,因此,我們知道,在胚胎中,當動物正在發育時,確實有相當長的尾巴。但一個基因啟動,將尾巴再吸收掉,將它去除了,所以這是另一個我們正在尋找的基因。我們要阻止這種尾巴被再吸收。

 

所以,我們現在真正嘗試做的是改造我們的雞,並製造出雞恐龍。(笑聲)。這是一隻看起來更酷的雞,但這只是相當基本的形式,所以這就是我們真正在做的東西。人們總是說,「為什麼要這麼做呢?為什麼做這個東西?有什麼好處呢?」嗯,這是個好問題。事實上,我認為這是教導孩子關於演化生物學和發育生物學,以及各式各樣的事物很棒的方式。坦白說,我認為如果Sanders上校(肯德基創辦人),如果他仔細琢磨對雞的形容,炸雞應該有額外的部位可以賣。(笑聲)

 

總之,當我們的雞恐龍孵化,很明顯的,海報上的孩子,或者你可以稱之為海報上的小雞,可以用於科技、娛樂和設計。

 

謝謝。

 

(掌聲)

 

以下為系統擷取之英文原文

About this talk

Renowned paleontologist Jack Horner has spent his career trying to reconstruct a dinosaur. He's found fossils with extraordinarily well-preserved blood vessels and soft tissues, but never intact DNA. So, in a new approach, he's taking living descendants of the dinosaur (chickens) and genetically engineering them to reactivate ancestral traits — including teeth, tails, and even hands — to make a "Chickenosaurus".

About Jack Horner

Jack Horner and his dig teams have discovered the first evidence of parental care in dinosaurs, extensive nesting grounds, evidence of dinosaur herds, and the world’s first dinosaur embryos. He's… Full bio and more links

Transcript

When I was growing up in Montana, I had two dreams. I wanted to be a paleontologist, a dinosaur paleontologist, and I wanted to have a pet dinosaur. And so that's what I've been striving for all of my life. I was very fortunate early in my career. I was fortunate in finding things. I wasn't very good at reading things. In fact, I don't read much of anything. I am extremely dyslexic, and so reading is the hardest thing I do. But instead, I go out and I find things. Then I just pick things up. I basically practice for finding money on the street. (Laughter) And I wander about the hills. And I have found a few things.

And I have been fortunate enough to find things like the first eggs in the Western hemisphere and the first baby dinosaurs in nests, the first dinosaur embryos and massive accumulations of bones. And it happened to be at a time when people were just starting to begin to realize that dinosaurs weren't the big, stupid, green reptiles that people had thought for so many years. People were starting to get an idea that dinosaurs were special.

And so, at that time, I was able to make some interesting hypotheses along with my colleagues. We were able to actually say that dinosaurs -- based on the evidence we had -- that dinosaurs built nests and lived in colonies and cared for their young, brought food to their babies and traveled in gigantic herds. So it was pretty interesting stuff. I have gone on to find more things and discover that dinosaurs really were very social. We have found a lot of evidence that dinosaurs changed from when they were juveniles to when they were adults. The appearance of them would have been different -- which it is in all social animals. In social groups of animals, the juveniles always look different than the adults. The adults can recognize the juveniles, the juveniles can recognize the adults. And so we're making a better picture of what a dinosaur looks like. And they didn't just all chase jeeps around.

(Laughter)

But it is that social thing that I guess attracted Michael Crichton. And in his book, he talked about the social animals. And then Steven Spielberg, of course, depicts these dinosaurs as being very social creatures. The theme of this story is building a dinosaur, and so we come to that part of "Jurassic Park." Michael Crichton really was one of the first people to talk about bringing dinosaurs back to life. You all know the story, right. I mean, I assume everyone here has seen "Jurassic Park."

If you want to make a dinosaur, you go out, you find yourself a piece of petrified tree sap -- otherwise known as amber -- that has some blood-sucking insects in it, good ones, and you get your insect and you drill into it and you suck out some DNA, because obviously all insects that sucked blood in those days sucked dinosaur DNA out. And you take your DNA back to the laboratory and you clone it. And I guess you inject it into maybe an ostrich egg, or something like that. And then you wait, and, lo and behold, out pops a little baby dinosaur. And everybody's happy about that. (Laughter) And they're happy over and over again. They keep doing it; they just keep making these things. And then, then, then, and then ... Then the dinosaurs, being social, act out their socialness. And they get together, and they conspire. And, of course, that's what makes Steven Spielberg's movie -- conspiring dinosaurs chasing people around.

So I assume everybody knows that if you actually had a piece of amber and it had an insect in it, and you drilled into it, and you got something out of that insect, and you cloned it, and you did it over and over and over again, you'd have a room full of mosquitoes. (Laughter) (Applause) And probably a whole bunch of trees as well.

Now if you want dinosaur DNA, I say go to the dinosaur. So that's what we've done. Back in 1993 when the movie came out, we actually had a grant from the National Science Foundation to attempt to extract DNA from a dinosaur. And we chose the dinosaur on the left, a Tyrannosaurus Rex, which was a very nice specimen. And one of my former doctoral students, Dr. Mary Schweitzer, actually had the background to do this sort of thing. And so she looked into the bone of this T. rex, one of the thigh bones, and she actually found some very interesting structures in there. They found these red circular-looking objects. And they looked for all the world like red blood cells. And they're in what appear to be the blood channels that go through the bone. And so she thought, well, what the heck. So she sampled some material out of it. Now it wasn't DNA; she didn't find DNA. But she did find heme, which is the biological foundation of hemoglobin. And that was really cool. That was interesting. That was -- here we have 65 million year-old heme. Well we tried and tried and we couldn't really get anything else out of it.

So a few years went by, and then we started the Hell Creek Project. And the Hell Creek Project was this massive undertaking to get as many dinosaurs as we could possibly find, and hopefully find some dinosaurs that had more material in them. And out in Eastern Montana there's a lot of space, a lot of badlands, and not very many people. And so you can go out there and find a lot of stuff. And we did find a lot of stuff. We found a lot of Tyrannosaurs, but we found one special Tyrannosaur, and we called it B-rex. And B-rex was found under a thousand cubic yards of rock. It wasn't a very complete T. rex, and it wasn't a very big T. rex, but it was a very special B-rex. And I and my colleagues cut into it, and we were able to determine, by looking at lines of arrested growth, some lines in it, that B-rex had died at the age of 16. We don't really know how long dinosaurs lived, because we haven't found the oldest one yet. But this one died at the age of 16.

We gave samples to Mary Schweitzer, and she was actually able to determine that B-rex was a female based on medullary tissue found on the inside of the bone. Medullary tissue is the calcium build-up, the calcium storage basically, when an animal is pregnant, when a bird is pregnant. So here was the character that linked birds and dinosaurs. But Mary went further. She took the bone, and she dumped it into acid. Now we all know that bones are fossilized, and so if you dump it into acid, there shouldn't be anything left. But there was something left. There were blood vessels left. There were flexible, clear blood vessels. And so here was the first soft tissue from a dinosaur. It was extraordinary. But she also found osteocytes, which are the cells that laid down the bones. And try and try, we could not find DNA, but she did find evidence of proteins.

But we thought maybe -- well, we thought maybe that the material was breaking down after it was coming out of the ground. We thought maybe it was deteriorating very fast. And so we built a laboratory in the back of an 18-wheeler trailer, and actually took the laboratory to the field where we could get better samples. And we did. We got better material. The cells looked better. The vessels looked better. Then the collagen. I mean, it was wonderful stuff. But it's not dinosaur DNA. So we have discovered that dinosaur DNA, and all DNA, just breaks down too fast. We're just not going to be able to do what they did in "Jurassic Park." We're not going to be able to make a dinosaur based on a dinosaur.

But birds are dinosaurs. Birds are living dinosaurs. We actually classify them as dinosaurs. We now call them non-avian dinosaurs and avian dinosaurs. So the non-avian dinosaurs are the big clunky ones that went extinct. Avian dinosaurs are our modern birds. So we don't have to make a dinosaur; because we already have them.

(Laughter)

I know, you're as bad as the sixth-graders. (Laughter) The sixth-graders look at it and they say, "No." (Laughter) "You can call it a dinosaur, but look at the velociraptor: the velociraptor is cool." (Laughter) "The chicken is not." (Laughter) So this is our problem, as you can imagine. The chicken is a dinosaur. I mean it really is. You can't argue with it, because we're the classifiers and we've classified it that way. (Laughter) (Applause) But the sixth-graders demand it. "Fix the chicken." (Laughter) So that's what I'm here to tell you about: how we are going to fix a chicken.

So we have a number of ways that we actually can fix the chicken. Because evolution works, we actually have some evolutionary tools. We'll call them biological modification tools. We have selection. And we know selection works. We started out with a wolf-like creature and we ended up with a Maltese. I mean, that's -- that's definitely genetic modification. Or any of the other funny looking little dogs. We also have transgenesis. Transgenesis is really cool too. That's where you take a gene out of one animal and stick it in another one. That's how people make GloFish. You take a glow gene out of a coral or a jellyfish and you stick it in a zebrafish, and, puff, they glow. And that's pretty cool. And they obviously make a lot of money off of them. And now they're making Glow rabbits and glow all sorts of things. I guess we could make a glow chicken. (Laughter) But I don't think that'll satisfy the sixth-graders either.

But there's another thing. There's what we call atavism activation. And atavism activation is basically -- an atavism is an ancestral characteristic. You heard that occasionally children are born with tails, and it's because it's an ancestral characteristic. And so there are a number of atavisms that can happen. Snakes are occasionally born with legs. And here's an example. This is a chicken with teeth. A fellow by the name of Matthew Harris at the University of Wisconsin in Madison actually figured out a way to stimulate the gene for teeth, and so was able to actually turn the tooth gene on and produce teeth in chickens. Now that's a good characteristic. We can save that one. We know we can use that. We can make a chicken with teeth. That's getting closer. That's better than a glowing chicken.

(Laughter)

A friend of mine, a colleague of mine, Dr. Hans Larsson at McGill University, is actually looking at atavisms. And he's looking at them by looking at the embryo genesis of birds and actually looking at how they develop. And he's interested in how birds actually lost their tail. He's also interested in the transformation of the arm, the hand, to the wing. He's looking for those genes as well. And I said, "Well, if you can find those, I can just reverse them and make what I need to make for the sixth-graders." And so he agreed. And so that's what we're looking into.

If you look at dinosaur hands, a velociraptor has that cool-looking hand with the claws on it. Archaeopteryx, which is a bird, a primitive bird, still has that very primitive hand. But as you can see, the pigeon, or a chicken or anything else, another bird, has kind of a weird looking hand, because the hand is a wing. But the cool thing is is that, if you look in the embryo, as the embryo is developing the hand actually looks pretty much like the archaeopteryx hand. It has the three fingers, the three digits. But a gene turns on that actually fuses those together. And so what we're looking for is that gene. We want to stop that gene from turning on, fusing those hands together, so we can get a chicken that hatches out with a three-fingered hand, like the archaeopteryx. And the same goes for the tails. Birds have basically rudimentary tails. And so we know that in embryo, as the animal is developing, it actually has a relatively long tail. But a gene turns on and resorbs the tail, gets rid of it. So that's the other gene we're looking for. We want to stop that tail from resorbing.

So what we're trying to do really is take our chicken, modify it and make the chickenosaurus. (Laughter) It's a cooler looking chicken. But it's just the very basics. So that really is what we're doing. And people always say, "Why do that? Why make this thing? What good is it?" Well, that's a good question. Actually, I think it's a great way to teach kids about evolutionary biology and developmental biology and all sorts of things. And quite frankly, I think if Colonel Sanders was to be careful how he worded it, he could actually advertise an extra piece. (Laughter)

Anyway -- When our dino-chicken hatches, it will be, obviously, the poster child, or what you might call a poster chick, for technology, entertainment and design.

Thank you.

(Applause)
 


留下您對本課程的評論
標題:
您目前為非會員,留言名稱將顯示「匿名非會員」
只能進行20字留言

留言內容:

驗證碼請輸入4 + 5 =

標籤

現有標籤:1
新增標籤:


有關本課程的討論

目前暫無評論,快來留言吧!

Creative Commons授權條款 本站一切著作係採用 Creative Commons 授權條款授權。
協助推廣單位: