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为什么蓝鲸不会得癌症?

Why Blue Whales Don't Get Cancer - Peto's Paradox

Cancer is a creepy and mysterious thing.
癌症可怕而又神秘
In the process of trying to understand it,
在试图了解它
to get better at killing it,
以及更好地杀死它的过程中
we discovered a biological paradox that remains unsolved to this day.
我们发现了一个直到现在都没有解决的生物悖论
Large animals seem to be immune to cancer,
大型动物似乎对癌症有免疫力
which doesn’t make any sense.
这就很难说通
The bigger a being, the more cancer it should have.
一种生物越大 它所会患的癌症应该越多
To understand why, we first need to take a look at the nature of cancer itself.
要了解其中原因 我们首先要了解癌症的本质
Kurzgesagt in a Nutshell
《科学坚果》
Our cells are protein robots made out of hundreds of millions of parts.
我们的细胞是由数亿零部件组成的蛋白质机器人
Guided only by chemical reactions,
它们只能通过化学反应
they create and dismantle structures,
来完成生物结构的合成与分解
sustain a metabolism to gain energy,
维持新陈代谢以获取能量
or make almost perfect copies of themselves.
或是进行几近完美的自我复制
We call these complex chemical reactions pathways.
我们称它们为复杂化学反应途径
They are biochemical networks upon networks,
它们是一个又一个的生化网络
intertwined and stacked on top of each other.
互相交织 彼此堆叠
Most of them can barely be comprehended by a single human mind,
对于其中的大部分 仅凭人类的头脑很难理解
and yet they functioned perfectly.
但它们依旧运作得很好
Until.. they don’t.
直到……出现了问题
With billions of trillions of reactions
多年来 数千个网络中
happening in thousands of networks over many years,
发生了数以万亿计的反应
the question is not if something will go wrong, but when.
问题不在于是否会出错 而是何时会出错
Tiny mistakes add up until the grandiose machinery gets corrupted.
量变引起质变 长堤溃于蚁穴
To prevent this from getting out of hand,
为了防止反应失控
our cells have kill switches that make them commit suicide.
我们的细胞有诱发自杀的开关
But these kill switches are not infallible.
但这些开关并非万无一失
If they fail, a cell can turn into a cancer cell.
如果失败了 细胞就有可能转变为癌细胞
Most of them are slained by the immune system very quickly.
大部分癌细胞会被免疫系统快速杀死
But this is a numbers game.
但这是一个数字游戏
Given enough time, a cell would accrue enough mistakes,
如果给了足够的时间 细胞就会累积足够多的错误
slipped by unnoticed and begin making more of itself.
总有一些逃过法眼 并越复制越多
All animals have to deal with this problem.
所有动物都不得不面对这个问题
In general, the cells of different animals are the same size.
一般来说 不动物的细胞大小是一样的
The cells of a mouse aren’t smaller than yours.
老鼠的细胞不比你的小
It just has fewer cells in total and a shorter lifespan.
只不过是总量较少 寿命更短
Fewer cells and a short life means
更少的细胞和更短的寿命意味着
a lower chance of things going wrong or cells mutating,
反应过程出错或是细胞变异的几率更小
or at least it should mean that.
或者至少应该如此
Humans live about 50 times longer and have 1,000 times more cells than mice,
人类的寿命是老鼠的50倍 拥有的细胞数量是老鼠的1000倍
yet the rate of cancer is basically the same in humans and in mice.
但人类和老鼠得癌症的概率却基本相同
Even waiter, blue whales with about 3,000 times more cells than humans
蓝鲸拥有的细胞数量大约是人类的3000倍
don’t seem to get cancer at all really.
但好像从来不会得癌症
This is Peto’s paradox,
这就是佩托悖论
the baffling realization
其令人费解的地方在于
that large animals have much much less cancer than they should.
大型动物的癌症发病率远远低于应该的发病率
Scientists think there are two main ways of explaining the paradox:
科学家认为有两个主要原因可以解释这个悖论
evolution and hyper tumors.
进化和超肿瘤
Solution one: evolve or become a blob of cancer.
解释一:进化或是变成一团肿瘤
As multicellular beings developed a 600 million years ago,
随着6亿年前多细胞生物的发展
animals became bigger and bigger,
动物变得越来越大
which added more and more cells
细胞数量也越来越多
and hence more and more chances that cells could be corrupted.
因此细胞被破坏的机会也就越来越多
So the collective had to invest in better and better cancer defenses,
所以全体生物必须寻求更好的癌症防御方法
the ones that did not died out.
以防自身物种的灭绝
But cancer doesn’t just happen.
但癌症不仅是发生那么简单
It’s a process that involves many individual mistakes
它是一个涉及到某一细胞内几个特定基因的
and mutations in several specific genes within the same cell.
不同错误与突变的过程
These genes are called proto-oncogenes and when they mutate it’s bad news.
这些基因被称作原癌基因 它们的突变是是十分糟糕的消息
For example with the right mutation,
比方说 突变方向对的话
a cell will lose its ability to kill itself.
细胞就会失去原有的自杀机制
Another mutation and it will develop the ability to hide.
有的突变会使细胞发展出隐藏自身的能力
Another and it will send out calls for resources.
有的会发出需求资源的信号
Another one and it will multiply quickly.
还有的会导致快速增殖
These oncogenes have an antagonist though;
但这些原癌基因有一种拮抗物
tumor suppressor genes.
抗癌基因
They prevent these critical mutations from happening
它们能防止发生严重的突变
or order the cell to kill itself if they decide it’s beyond repair.
或者当细胞无法修复时会命令细胞自杀
It turns out that large animals have an increased number of them.
事实证明 大型动物的抗癌基因是有增加的
Because of this, elephant cells require more mutations
正因如此 大象得癌症所需的细胞突变
than mice cells to develop a tumor.
要比老鼠多
They are not immune but more resilient.
并非能够免疫 而是抗性增强了
This adaption probably comes with a cost in some form
这种适应可能会带来某种形式的成本的增加
but researchers still aren’t sure what it is.
但研究人员仍不能确定其具体是什么
Maybe tumor suppressors make elephants age quicker later in life
也许抗癌基因会使大象在生命后期衰老得更快
or slow down how quickly injuries heal.
或是使伤口愈合变得更慢
We don’t know yet.
我们目前仍不得知
But the solution to the paradox may actually be something different.
但是 对这个悖论的解释可能是另一回事
“Hypertumors”
超肿瘤
Solution 2: Hypertumors
解释二:超肿瘤
Yes,
是的
really.
没错
Hypertumors are named after hyperparasites: the parasites of parasites.
超肿瘤的命名源于寄生虫的寄生虫:超寄生虫(或重寄生虫等)
Hypertumors are the tumors of tumors.
超肿瘤就是肿瘤的肿瘤
Cancer can be thought of as a breakdown in cooperation.
癌症可以认为是一种合作上的失败
Normally, cells work together to form structures
正常来说 细胞共同合作组成生物结构
like organs, tissue or elements of the immune system.
比如器官 组织或是免疫系统的各部分等
But cancer cells are selfish and only work for their own short-term benefit.
但癌细胞非常自私 只会顾及它们自身的短期利益
If they’re successful, they form tumors,
如果成功了 它们就会形成肿瘤这种
huge cancer collectives that can be very hard to kill.
很难被杀死的巨大癌症集团
Making a tumor is hard work though.
形成肿瘤很难
Millions or billions of cancer cells multiply rapidly,
数百万或数亿的癌细胞快速增殖
which requires a lot of resources and energy.
而这需要大量的资源和能量
The amount of nutrients they can steal from the body becomes the limiting factor for growth.
它们能从身体偷取的营养量是限制其生长的因素
So the tumor cells trick the body
所以肿瘤细胞欺骗身体
to build new blood vessels directly to the tumor, to feed the thing killing it.
让其直接在肿瘤上建造新的血管 以喂养这个杀死自己的凶手
And here, the nature of cancer cells may become their own undoing.
这样的情况下 癌细胞的天性可能会让它们毁灭自我
Cancer cells are inherently unstable and so they can continue to mutate.
癌细胞天生不稳定 所以它们可以持续变异
Some of them faster than their buddies.
有些会比同类变异得更快
If they do this for a while,
如果这样持续了一段时间
at some point, one of the copies of the copies of the original cancer cell,
在某个时刻 原始癌细胞的某一代复制品中的一个
might suddenly think of itself as an individual again
可能突然再次把自己当成了独立个体
and stop cooperating,
然后停止之前的合作
which means just like the body,
也就意味着 像人体一样
the original tumor suddenly becomes an enemy,
原始的肿瘤突然变成了敌人
fighting for the same scarce nutrients and resources.
要为同样的稀缺营养和资源而战
So the newly mutated cells can create a hypertumor.
那么新变异的细胞就会产生超肿瘤
Instead of helping, they cut off the blood supply to their former buddies,
恩将仇报 它们切断了以前伙伴的血液供应
which will starve and kill the original cancer cells.
这样就会饿死原始的癌细胞
Cancer is killing cancer.
是癌杀了癌
This process can repeat over and over,
这个过程会多次重复
and this may prevent cancer from becoming a problem for a large organism.
而这会防止癌症成为大型有机体的麻烦
It is possible that large animals have more of these hyper tumors than we realize,
大型动物的超肿瘤有可能比我们知道的更多
they might just not become big enough to notice,
它们也许还没大到引起注意
which makes sense, a two gram tumor is 10% of a mouse’s body weight,
这也说得通 一个两克重的肿瘤占老鼠体重的10%
while It’s less than 0.002% of a human,
而对于人类 占比少于0.002%
and 0.000002% of a blue whale.
到了蓝鲸 仅占比0.000002%
All three tumors require the same number of cell divisions
三个肿瘤都需要相同数量的细胞分裂
and have the same number of cells.
并且有相同数量的细胞
So an old blue whale might be filled with tiny cancers and just not care.
所以一头年老的蓝鲸可能浑身都有微小的癌症 但它并不在乎
There are other proposed solutions to Peto’s paradox,
还有其他针对佩托悖论的解释
such as different metabolic rates
比如不同的代谢率
or different cellular architecture.
或是不同的细胞结构
But right now we just don’t know.
但目前我们并不清楚
Scientists are working on the problem.
科学家们正在研究这个问题
Figuring out how large animals are so resilient to one of the most deadly diseases we know,
弄清楚大型动物对这种最致命的疾病之一的抵抗力从何而来
could open the path to new therapies and treatments.
能开拓通向新治疗方法的道路
Cancer has always been a challenge.
癌症从来都是一个挑战
Today, we are finally beginning to understand it
如今 我们终于开始了解它
and by doing so, one day we might finally overcome it.
藉此有一天我们可能会最终战胜它
This video was sponsored by…
本视频的赞助商是……
YOU!
你们!
If you want to help us make more,
如果你想帮助我们制作更多视频
you can do so by supporting us on Patreon,
可以到Patreon上支持我们
or getting one of the beautiful things we’ve made,
或者是购买我们漂亮的周边产品
like our Space Explorer Notebook
比如我们的太空探险家笔记本
with infographic pages and unique grits to inspire your creativity,
里面自带的图表信息页和独特磨砂能激发你的创造力
or an infographic poster bundle,
或者是信息图表海报
or the very comfit Kurzgesagt hoodie,
或是非常舒服的Kurzgesagt帽衫
or if you missed it the first time,
又或者如果没赶上第一期的话
the second run of our gratitude journal.
可以买我们第二期的感恩日记
We put a lot of time and love into our merch,
我们在产品上投入了很多时间和爱
because just like with our videos,
因为就像我们的视频一样
we only want to put things into the world that we feel good about.
我们只想把我们认为美好的东西展示给这个世界
Kurzgesagt is a project that by rights shouldn’t really work.
按理来说 Kurzgesagt应该是个很难做下去的项目
Videos like the one you just watched take months to finish
像你们看到的这个视频需要花费数月来完成
and we’re only able to put in so much time,
我们之所以能投入这么多时间
because of your direct support,
正是因为有你们的支持
because you watch and share and because you care.
因为有你们的观看 分享 以及你们的关注
Thank you for watching.
感谢您的收看

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视频概述

癌症是怎么产生的?大型动物为什么不会得癌症?一起来看看视频

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视频来源

https://www.youtube.com/watch?v=1AElONvi9WQ

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