And we're still dying to know.

我們仍百思不得其解。

Which came first? The chicken, or the egg? The question would be simple if we took it literally.

哪個先出現？先有雞還是先有蛋？如果單純以字面來解釋問題會簡單很多。

Egg-laying animals existed far before chickens came about, so technically the egg came before the chicken.

卵生動物早在雞出現前就存在了，所以技術上來說「蛋」先於雞。

But this question, better worded as the "chicken or the chicken egg" focuses more on the cyclical cause and consequence.

但問題應該這樣表達：「先有雞還是先有『雞蛋』？」更著重在兩者間的先後順序和因果關係。

That is, if a chicken is born from an egg, where did the egg come from?

如果雞是從蛋裡孵出來的，那蛋是從哪裡來的？

Another chicken, presumably, which, too, must have come from an egg, so which came first?

可能是另一隻雞，而它也必須從蛋裡孵出來，所以到底是哪個先？

On the one side, we have team chicken.

有一派支持先有「雞」。

Research suggests that the protein essential for the formation of chicken eggs, called OV-17, is only found in chicken ovaries.

研究指出:雞蛋形成的關鍵蛋白質「OV-17 蛋白」只能在雞的卵巢找到。

Without it the chicken eggshell could not be formed.

若沒有它，蛋殼便無法成型。

So without a chicken, you technically can't get a chicken egg.

所以若沒有雞，基本上不可能有雞蛋。

But this all depends on the nature and definition of a chicken egg in the first place.

但這其實都取決於雞蛋的本質和定義。

After all, is a chicken egg an egg laid by a chicken?

畢竟，雞蛋指的是「由雞下的蛋」？

Or one that simply contains a chicken?

還是「裡面有雞的蛋」？

Obviously, the OV-17-bearing chicken had to come from somewhere.

顯然地，擁有「OV-17 蛋白」的雞一定其來有自。

But if an elephant laid an egg from which a lion hatched, would it be an elephant egg or a lion egg?

但如果一隻大象下了顆蛋並孵出了獅子，那它是顆大象蛋還是獅子蛋？

This leads to the other side of the story, team egg.

要討論這個問題我們必須要聽聽另一派怎麼說，也就是支持先有「蛋」的人。

During reproduction, two organisms pass along their genetic information in the form of DNA.

在繁殖時，兩個有機體以 DNA 的形式傳承他們的基因資訊。

But the replication of this DNA is never one hundred percent accurate.

但是 DNA 的複製不可能百分之百精準。

And often produces minor changes for the new organism.

而常常會在新的有機體身上製造出微小的改變。

These small mutations in DNA over thousands of generations create new species.

這些 DNA 的小變化在數千代之後創造了新的品種。

But these genetic mutations must occur in the zygote or initial cell, so a creature very similar to a chicken (which we could call a porto-chicken would have mated with another proto-chicken and because of a small genetic mutation created the first chicken, which grew in an egg.

但這些基因變化必須發生在受精卵或原始細胞，所以一個很接近雞的生物 (我們稱之為「原型雞」)，要與另一隻原型雞配對，同時因為微小的基因變化，而創造出第一隻雞，而它由蛋所生。

So the egg came first? Well, team chicken might argue that this was simply a chicken growing inside of a proto-chicken egg.

所以是蛋先出現的？認為雞先出現的支持者可能會說這只是一隻雞生長在原型雞蛋中。

However, no one mutation can ever really constitute a new species.

但沒有任何一個小突變可以真的產生一個新品種。

Even though we humans like to classify all creatures into different groups and names, this is based on how things currently are, and not how they were millions of years ago.

即使人類喜歡將所有生物分類並冠上不同的名字，分類的依據是根據現存的生物，而非它們百萬年前的狀態。

The process of evolution is so gradual that no one proto-chicken-to-chicken birth could really be considered a new species at the time.

演化的過程是如此緩慢以致於沒有任何原型雞生出的雞可以真的在當下被視為一種新品種。

Much like how dogs have come from wolves, as humans began to interact with and domesticate wolves,

就像狗是從狼演化而來，過程中人類開始與狼互動、豢養它們。

There was no one single point where a wolf gave birth to a dog.

並沒有單一時間點讓狼突然就生出了狗。

But rather, as particular traits came about from selective pressures.

但有些特殊的特質是來自選擇壓力。

Such as choosing wolves who were not afraid of humans, or ones that were less aggressive.

例如：選擇不怕人或是較不具攻擊性的狼。

Over many generations we can see big genetic and behavioral trait differences.

好幾代之後，我們可以觀察到非常大的基因和行為特質差異。

"So, where does this leave us?" We're left with two scenarios.

所以這告訴我們什麼？剩下兩種可能性。

Some early egg-laying species gradually led to the creation of the proto-chicken which laid proto-chicken eggs.

某些早期的卵生物種逐漸演化出原型雞，而原型雞產下原型蛋。

In one of these eggs, there was a mutation causing a slight change and selective advantage.

其中一顆蛋產生基因變化，造成些微轉變和選擇優勢。

And this was ultimately the first chicken which then went on to lay chicken eggs.

而這最後變成了第一隻雞，而後它產下了雞蛋。

In this case, the chicken technically came first.

在這個案例中，理論上是雞先出現的。

Or we have a proto-chicken which gave birth to a chicken inside of what we would classify as a chicken egg and as such the egg came first.

或者，有一隻原型雞生出了一顆我們認為是雞蛋的蛋，裡面包含了一隻雞，如此便是蛋先出現。

Which brings us back to the nomenclature and question of, what is a chicken egg?

而這就帶我們回到命名法的問題：到底什麼是雞蛋？

Which is a fairly meaningless question, but at the end of the day, what we can all agree on is that regardless of whether it was a chicken egg or a proto-chicken egg, the first true chicken came from an egg.

這基本是個毫無意義的問題，但到頭來，我們都同意無論是雞蛋或是原型雞蛋，第一隻真正的雞都是來自一顆蛋。

The egg came first.

因此是蛋先出現的！

Got a burning question you want answered? Ask it in the comments, or on facebook and twitter.

有很想問的問題嗎？你可以在評論裡提問，或在臉書、推特提問。

And subscribe for more weekly science videos.

並訂閱頻道，每週觀賞科學影片。