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This one’s real easy, you guys--super low key, not really a big deal,
这个问题真的很简单，伙计们——非常接地气，没什么大不了的，
it’s just this silly question that nobody’s really interested in, it’s just like….how did life begin?
这只是一个没人真正感兴趣的愚蠢问题，这个问题就是……生命是如何开始的？
Ok, obviously I’m joking.
好吧，显然，我是在开玩笑啦。
This is one of the biggest unanswered questions in science today,
这个问题是当今科学界最大的未解之谜之一，
and is the backbone of our burning questions about who we are, where we come from, and if we’re alone out here.
也是我们是谁，我们来自哪里以及我们是不是宇宙中唯一的生物这些我们迫切想要知道答案的问题的支柱。
New research has now given us clues into how exactly the fundamental molecular building blocks of life came together in the first place.
现在，一项新的研究为我们提供了帮助我们弄清生命的基本分子结构究竟是如何组合在一起的新线索。
Because that’s the central question:
因为这一组合方式问题是揭开生命起源问题的关键：
in the big puddly soup of pre-biotic earth--as in, earth before living organisms--
在前生物时代那个浑浊的液态地球上——也即在生物出现之前的地球上——
how did the perfect ingredients for life form,
适合进化出生命的那些成分是如何形成的，
much less fuse together into something that stores information and can replicate independently.
更不用说融合成能够存储信息并独立复制的东西了。
A primer on how our living cell’s work:
我们先来介绍一下活细胞的工作原理：
A cell’s most important components are DNA, RNA and a ribosome.
细胞最重要的成分是DNA、RNA和核糖体。
DNA codes for all of the essential information about what the organism is and how it works,
DNA能够编码所有关于生物体的性质和工作原理的基本信息，
but it’s kept all safe and huddled away in the nucleus.
但DNA是安全地挤在细胞核里的。
To take that information and make it into actual stuff, like proteins,
要把这些信息转化成实际的东西，比如蛋白质，
an enzyme called RNA polymerase copies sections of the DNA and makes strands of RNA, which are a like one-sided version of DNA.
一种叫做“RNA聚合酶”的酶就要复制DNA的部分片段，合成“RNA链”这种类似于DNA单链的东西。
These messenger RNA strands get sent to the cell’s ribosome,
这些信使RNA链会被运送到细胞的核糖体，
where they’re converted into the proteins our cells need for survival.
在那里转化成细胞生存所需的蛋白质。
When scientists were first discovering all this complex stuff,
科学家们刚发现这些复杂的东西时，
it became an even bigger question of how all this could have spontaneously come together as a result of organic chemistry.
一个更大的问题出现了：有机化学是如何把所有这些活动自发地结合在一起的？
To tackle this problem, some scientists suggested that perhaps life as we know it now didn’t all spontaneously form at once exactly as it is,
为了解决这个问题，一些科学家提出，也许我们现在所知道的生命并不是像现实那样同时自发形成的，
it was probably a little simpler...maybe it was only RNA-based!
可能更简单一些……也许RNA才是它的源头也说不定！
This hypothetical situation is what we refer to as the RNA world.
这个假设的情况就是我们所说的“RNA世界”。
But this track of thinking is based on the idea that the self-replicating aspect of life is what formed first.
但这种思维方式是基于生命自我复制的一面是最先形成的这样一种观点的。
And not everyone agrees.
然而，并不是所有人都同意这一说法。
Some people think that metabolization, or the ability to extract energy from your environment, must have come first,
有些人则认为新陈代谢，就是从你的环境中提取能量的能力，肯定是最先出现的，
while a third camp thinks that compartmentalisation must have come first, a primitive version of the different internal pieces of a cell.
第三种看法则认为，“细胞内区室化”，即细胞内部不同部分的原始形态，肯定是最先出现的。
These divisions in the scientific community still survive,
即便是今天，科学界的这类分歧也依然存在，
but as we’ve come to learn more about RNA and how it can behave,
但随着我们对RNA及其行为的了解越来越多，
it’s become clearer that it’s an essential part of the beginning of life, if not the first thing that formed.
我们越来越清楚地认识到，RNA即便不是生命的起源，也是生命起源的重要组成部分。
This is because RNA can do a really exciting thing.
这是因为RNA有一个非常赞的功能。
Not only can it contain information that it can then replicate.
它不仅可以携带之后它将复制的信息。
but it can also fold itself up into shapes in which it can act as an catalyst, influencing chemical reactions!
还可以把自己折叠成各种形状，充当催化剂，左右化学反应!
When this was discovered, we realized it was much more likely that RNA-based life could indeed have survived and replicated all on its own.
发现了这一点后，我们意识到，更有可能的是，以RNA为基础的生命确实能够完全依靠自身存活下来，完成复制，
without the all the fancy add-ons we have today.
根本就不需要我们今天给它们安的那些花哨的附加配件。
So then we come down to the question again--how did RNA form in the first place?
那我们就又回到了下面这个问题上——RNA最初是如何形成的?
Scientists have been on a quest to demonstrate how all of RNA’s component parts could have spontaneously assembled,
科学家们一直在致力于证明RNA的所有组成部分是如何自发组装的，
and new research may just bring it all together.
新研究或许能把一切都拼凑起来。
RNA is made up of the nucleic acids cytosine, uracil, adenine, and guanine.
RNA是由核酸、胞嘧啶、尿嘧啶、腺嘌呤和鸟嘌呤组成。
A research team had shown a few years ago
几年前，一个研究小组就证明，
that a set of five simple compounds could have given rise to cytosine and uracil with nothing more than the addition of UV light,
一系列这五种简单的化合物组成的RNA只需要在紫外线的条件下就能产生胞嘧啶和尿嘧啶，
which there was plenty of on a primitive earth.
而在原始的地球上紫外线是很充足的。
A different team then showed a similarly easy and plausible process for the formation of adenine and guanine from simple building block elements.
后来，另一个研究小组也通过一个类似的，既简单又可信的过程展示了简单的基本元素如何转化成腺嘌呤和鸟嘌呤。
But no one had demonstrated that these two separate reactions, producing all four RNA nucleic acids, could have occurred in the same place at the same time.
但没有人证明这两种生成全部四种RNA核酸的独立反应能够同时发生在同一位置。
Until now.
直到现在。
A paper that came out in 2018 showed that a simple set of molecules--
2018年发表的一篇论文显示，一组简单的分子——
oxygen, nitrogen, methane, ammonia, water, and hydrogen cyanide, all of which would have been present on an early version of earth--
氧、氮、甲烷、氨、水和氰化氢，所有这些都可能存在于早期的地球上——
could react to form what we recognize as the uracil, adenine, guanine and cytosine.
是可以发生反应，产生我们所知的尿嘧啶、腺嘌呤、鸟嘌呤和胞嘧啶的。
This work is the first experimental evidence showing that the chemistry fits--these building blocks could have feasibly all come together at the same time, in the same place, we saw it happen before our very eyes.
这项工作是第一个实验证据，证明了这些化学成分是吻合的——这些构成要素是可能在同一时间、同一地点出现的，因为我们已经亲眼看到了。
There are still a couple of missing pieces that we haven’t been able to recreate in the lab.
不过，还是有一些缺失的片段是我们无法在实验室中重现的。
For instance, how did each of the building blocks come together to link them into the long chains that take them from nucleic acids to actual RNA?
比如，每一个要素是如何组合在一起，连接成从核酸变成实际RNA的长链的?
And, keep in mind, while the RNA world is the leading theory,
还有，记住了，虽然RNA世界是主要的理论，
there is some contention among scientists about the first inklings of life on earth.
科学家们对地球上最早的生命迹象还是有一些争论。
Hopefully work like this will add to that discussion,
希望本期视频也能成为讨论的一部分，
PLUS it does represent an unprecedented step forward in answering the most fundamental of questions: how life began.
何况，这期视频确实代表着在回答生命起源这一最基本问题上迈出了前所未有的一步。
For more on DNA and the craziness of life,
想了解更多关于DNA和生活的疯狂程度的信息，
check out another video of mine here.
请查看这一期的视频。
Don’t forget to subscribe to Seeker for all your genetic information questions, and thanks so much for watching
不要忘记订阅我们的《科学探索之旅》获取关于起源方面的问题，感谢大家的收看！
