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表观遗传学

Epigenetics

Sci Show
科学秀
So say you have a clone or a secret identical twin
假如你有一个克隆人 或者是同卵双胞胎
because you know that a twin or clone
由于双胞胎或是克隆人
is a genetically identical person to you, which is crazy!
从基因的角度上来说和你是同一个人 这有点疯狂
But it’s true.
但这的确是真实的
Anyway,so you have this clone or twin
不管怎样 你现在有了克隆人或是双胞胎
What have your parents decide that it’s too much trouble to keep both of you
你父母会觉得同时养你们两个太麻烦了
And so they give your clone to a
于是他们把你的克隆人送给了
kind of sketchy traveling circus.
一个条件恶劣的巡回马戏团
Now I know your parents probably wouldn’t actually do this,
我知道你的父母可能不会这么做
but just roll with me for a minute.
但请和我一起畅想
So for the purposes of this example let’s just say
举这个例子目的是说明
that you grew up living a normal suburban
你成长在无忧无虑的郊区中
American life while your clone grew up with less stability
享受着正常的美国式生活 而克隆人的生活却颠沛流离
and less access to nutritious food and less education.
缺少有营养的食物和必要的教育
But more exercise and more access
但也接受了更多的训练
to sword swallowers
并且接触了更多会吞剑的人
and bearded ladies.
或是有胡子的女人
And let’s say you guys are 50 years old, whatever,
假设你们已经50岁了 不管如何
you get together and have some lunch.
你们又团聚了并且一起吃饭
So you sit in there across the table from your clone.
于是你和你的克隆人坐在饭桌的两端
What do you think you see?
你猜你会看到什么?
Well for starters, Clone probably has a tattoo on its face.
首先 克隆人的脸上可能有刺青
And if Clone had stayed in the circus.
并且如果他一直留在马戏团中
Clone probably, you know, professionally rides a unicycle over a tightrope,
克隆人可能会熟练地在钢索上骑独轮车
so Clone is probably in pretty good shape.
于是他保持着不错的体型
But then again Clone probably smoked cigarettes and
但话说回来 克隆人可能会抽烟
probably was malnourished as a child so might be slightly shorter than you
并且由于幼年时营养不良 他的个头比你要矮
By the same token, let’s say that
同样假设你从1992年开始
you’ve been eating sonic tater tots five days a week since 1992
每周都吃油炸土豆泥
so you’re looking a little bit tubby.
于是你看起来就会有一点笨拙
Plus, you spent the last 20 years at a really stressful job that puts you at risk
此外 你过去20年一直从事非常有压力的工作
for all kinds of weird health complications.
这使你有患上各种健康并发症的风险
So at 50, you and Clone would probably look pretty different from one another.
于是你和克隆人在五十岁时可能有很大的不同
But it turns out you don’t just look different.
但事实上 你们不仅仅是看起来不同
You actually have become different.
你们实际上也变得不同了
Now, if some scientists looked at your genetic code
现在 假如科学家观察你们的基因序列
they would say that your DNA was still exactly the same as that other person.
他们会发现你的基因仍和克隆人一样
That is to say, if your genome is a paragraph
也就是说 如果你的基因是一段文字的话
all of the letters would be in the exact same word
所有的单词都是完全一样的
But on another level
但在另一个层面上
there would be a huge difference
会发生巨大的变化
and if we extend this metaphor
而且如果我们将这个比喻拓展
we can say that the letters are in the same order
我们就可以在不改变单词顺序的情况下
but the spaces in the punctuation are all in different places
通过改变标点符号和停顿
of course completely
彻底地
potentially changing the message of that paragraph.
使整段文字的意思被完全改变
The study of this genetic punctuation that I’m talking about
这项我所谈论的关于遗传标点的研究
is called epigenetics which literally means above genetics
叫做表观遗传学 字面意思是在遗传学之上
The epigenome doesn’t change your DNA
表观基因组并不会改变你的DNA
But it decides how much or whether some genes are
但是它决定了在你身体中是否会表达一些基因
expressed in different cells in your body
或是表达多少在你的体内
Epigenetics looks at what happens to
表观遗传学研究的是
your genes over the course of your life
在你生命过程中基因发生了什么
and whether those changes could be passed down to your children
这些改变是如何和遗传给你的孩子
or even your grandchildren
甚至你的孙辈的
So here’s the way epigenetics works
这便是表观遗传学工作的方式
you have billions of cells in your body
你的身体中有几十亿个细胞
and they each contain your DNA
每一个都包含着与你的遗传密码
the same exact blueprint of your genetic code
有完全相同的模型的DNA
But just because they have the DNA
但是它们仅仅拥有DNA
it doesn’t mean that they know what to do with it
这不意味着它们知道该如何处理它
They need outside instruction from these
它们需要外界的这些
little carbon and hydrogen compounds called methyl groups.
由微小碳氢化合物组成的甲基的指导
The way these Methyl groups control the genome is by binding to a gene
甲基调控基因组的方式是连接到基因上
and saying do not express this gene.
并且使基因不表达
The methyl groups bind differently to your genome
甲基和你的基因组以不同的方式结合
and a skin cell versus say a tongue cell or an eyeball cell
于是一个肌肉细胞 或是舌细胞抑或是眼球细胞
and that is one of the ways that a cell knows that
通过这种方式(这是其中一种方式)
hey, I’m the skin cell or hey,I’m an eyeball cell hey, I’m a muscle Cell.
知道了它们自己的身份
In addition to Methyl groups epigenetics is also controlled by histones
表观遗传学不仅被甲基调控 还被组蛋白调控
which are proteins that are basically the spools that DNA winds itself around.
这些蛋白质本质上是DNA缠绕自身的线轴
Histones can change how tightly or loosely the DNA is wound around them
组蛋白可以改变DNA缠绕的松紧程度
if they’re more loosely wound the genes can express more
如果它们缠绕地更松 那么基因就能表达得更多
and if they’re more tightly round than they express less
反之则表达得更少
so whereas the Methyl groups are more like a switch
然而甲基更像是一个开关
the histones are more like a knob
组蛋白而更像旋钮
Every cell and your body
你身体中的每个细胞
has a distinct methylation and histone pattern
都有着截然不同的甲基化 和组蛋白模式
and that is what gives every cell its marching orders.
这就是赋予每个细胞行进顺序的原因
Think of your genome the DNA is the actual hardware of the computer
对于基因组来说 DNA实际上是电脑的硬件
While the epigenome is more like the software which tells the hardware what to do.
而表观基因组更像是指导硬件的软件
The genome is what’s going to be doing all the work
基因组将完成所有工作
but the epigenome is going to be telling it what to do.
但是表观基因组告诉它要做什么
So the hardware of your DNA
于是在你的一生中
is going to be the same throughout your entire life,
硬件DNA会始终如一
but these epigenetic tags do change throughout your life
但是这些表观遗传标签是会改变的
And they decide what genes get expressed or not.
它们决定了哪些基因进行或是不进行表达
Now epigenetic information in a cell isn’t permanent
现在我们知道表观遗传信息不是永久的
it can change throughout your life, and it can be hereditary
他可以在你的生命中改变 并且它是可遗传的
And it can change over time
它可以随时间改变
especially when your body is going through a lot of changes
尤其是在你的身体经历一系列变化的时候
like say during puberty
比如在青春期
A bunch of Methyl groups kick in they’re like
一群甲基就发挥作用了 它们就像是说
Okay so you guys over here
你们这些家伙
You’re gonna have to start growing hair
准备开始长胡子
and you guys over here
你们那些家伙
I really need you guys to get behind
我真的很需要你们给这个人
giving this guy’s some really horrible acne
一些非常严重的青春痘
or like when you get pregnant which hopefully I won’t
或者是当你怀孕的时候 但愿我不会
but when you do your epigenome has to be like
但当这时你的表观基因组就会说
alright guys everything’s about to get a whole lot bigger in here
伙计们 把这里所有的东西都变大
And we’re gonna have to pass something the size of like a miriam Webster’s dictionary
我们要把像韦氏词典这么大的东西
through that little pipe over there
送到那个小管子里去
So let’s get this thing done
所以让我们加把劲
but it’s not just these dramatic times
但是并不只是这些特殊的时刻
when the epigenome is changing
表观基因组才发生改变
It changes suddenly throughout our entire lives
在我们的一生中它总是突然改变
and it changes based on a lot of environmental factors
而且这些改变是基于一系列环境因素的
like what we do what we eat
比如我们做了什么 我们吃了什么
what we smoke and how stressed out we are in a daily basis
抽的烟以及我们日常生活有多大的压力
Scientists have found that things like a bad diet
科学家发现诸如不良饮食之类的事情
can actually lead to Methyl groups binding to the wrong place and making mistakes.
可能导致甲基结合到错误的位置上并犯错
And with those bad instructions
受这些错误的指导
cells become abnormal and become a disease
细胞变得异常并且导致了疾病的发生
and then basically all hell breaks loose
然后一切都乱了套
and you get cancer or something.
于是你患上了癌症或是其他疾病
Epigenetics is a very young science
表观遗传学是一门新兴的科学
though we’ve known about the epigenome since the 1970s
尽管我们在1970年代就知道表观遗传基因组了
It’s only in the last 20 years that we’ve even known
但直到过去的20年中 我们才知道
what effect these epigenetic tags are having on our DNA.
这些表观遗传标签对我们的DNA有什么影响
And even after they got all that business straight
甚至在他们把所有的事都搞清楚之后
Scientists still thought
科学家们仍然认为
that all of our epigenetic tags were stripped off of our genome
全部表观遗传标签 在传递给孩子之前
before they were passed on to our children
都已经从基因组中剥离了
So if you started smoking 10 packs a day when you were 10 years old
因此如果你从十岁开始每天抽十包烟
that would certainly be a horrible health decision for you
那对你的健康当然有着可怕的危害
But you wouldn’t necessarily be harming your unborn children in any measurable way.
但你不一定会对你未出生的孩子造成多大的伤害
However the thinking on that is changing pretty rapidly
然而 这种想法正在迅速被改变
because it’s true that a lot even most of the
因为开始的几天 的确有很多甚至是大部分
epigenetic information from a parent
来自父母的表观遗传信息
is stripped off of the embryos genome in the first few days
都从胚胎基因组中剥离出来
and fresh ones are created specifically for this new person.
并且这个新生儿获得了全新的信息
However some of these tags get stuck on the genome and are passed down from generation to generation
但是 其中一些标签留在基因组上 并世代相传
and it just so happens that the more they study this the more it looks like
碰巧的是 他们研究的越多
bad epigenetic information is being passed from generation to generation
发现不良的表观遗传信息就越可能代代相传
and this is a whole new way to think about how we pass information between generations
这使我们重新思考遗传信息如何在几代人之间传递
Your grandmother was making dietary decisions that affect you today
你的祖母正在做出影响你今天的饮食决定
As we experience all these new strange epidemics diabetes autoimmune disorders cancers
因为我们经历了前代未曾出现的所有这些
that weren’t appearing in previous generations
全新的奇怪的流行病 糖尿病 自身免疫性疾病
It’s starting to look like these may be caused by
看起来这些可能是由父母传下来的
epigenetic information passed down from our parents
表观遗传信息引起的
I know it’s such an unbelievable Buzzkill
我知道这是一个令人难以置信的扫兴的消息
There is no point in our lives when we can do anything
当我们做任何事情都不再感到内疚的时候
without guilt anymore
我们的生活就没有意义了
The discovery that the environmental factors the parent experiences
20世纪80年代 一项发现表明
can be passed down from generation to generation was sparked in the 1980s
父母经历的环境因素可以一代一代地遗传下去
and this happen when some scientists were looking at the birth and death records of some people
当一些科学家查看19世纪出生于瑞典的
who lived in nineteenth-century Sweden
某些人的出生和死亡记录时 这种情况就发生了
as is a weird place to find a genetic revolution but there it is
这是寻找基因革命不可思议的地方
wasn’t just any place in Sweden
但并非是位于瑞典全境
It was in Norrbotten,which is the Northernmost County in Sweden
而是位于瑞典最北端的北博滕
which is literally in the arctic circle
北博滕字面的意思是处于北极圈内
and despite the fact that norrbotten was literally the worst place
尽管事实上北博滕可能是
you could possibly choose to live in Sweden,
在瑞典居住最糟糕的地方
there were some people living there in the 1800s
有人1800年代就居住在那里
and they were completely cut off from the rest of the world
他们与世界其他地方完全隔绝
Let me clarify
让我澄清一下
these people were isolated
这些人基本与世隔绝
like if they didn’t have a good crop year people died
比如假设他们遇到了收成不好的一年 他们就饿死了
No, it wasn’t ideal
这倒不是我们所希望的
but you know they didn’t ask me my opinion
但是你也知道他们可没问我的意见
So I’m not giving it
所以我对此不予置评
So anyway these people subsisted entirely on what they grew when the animals that they raised
无论如何 这些人完全依靠饲养动物来维持生活
and like I said sometimes they starved
就像我说的 有时候他们忍饥挨饿
but sometimes they had huge bountiful years of plenty
但有时候他们会有丰收的一年
and what happened people totally went ape crackers.
这会使人们像发了疯的猿猴
I mean of course they did because they were so freakin hungry
我是说 他们当然会这样 因为他们饿坏了
and then all of a sudden there was all this damn food everywhere.
然后忽然到处都是该死的食物
Anyway there was a public health specialist
无论如何 有一个公共卫生专家在那里
who was looking at the effects of the people who grew up in the really bad starving periods of time
观察长时间挨饿对人成长的影响
versus the people who grew up in the
与那些每天吃山珍海味
eat all you can at the smorgasbord years.
享用自助餐成长的人进行对比
You might already be guessing what they found out.
你可能也猜到了他们会发现什么
people who went from relatively slim pickins
那些相对很瘦弱的小孩
to feed your face until you have to barf and
顿顿都吃到撑的孩子
then do it all over again in a single season.
如果天天都这么暴饮暴食
Those people dead at an average of six years sooner than they’re starved out counterparts,
他们的寿命要比常挨饿的人平均短六年
and you know it sucks
但这很糟糕
, so do their kids so do their kids‘ kids
因为他们的孩子以及孩子的孩子也是这样
boom epigenetics
爆炸的表观遗传学
So of course now we all know
于是我们都知道
and we’re all going to stop doing unhealthy things starting today
从今天开始要停止做不健康的事
Unless the damage is already done the damage is
除非损害已经造成了
almost certainly already done, but hey
损害几乎一定是已经无法挽回了 但是 嘿
epigenetics brings good tidings along with bad ones
表观遗传学带来坏消息的同时也带来了好消息
for instance
举例来说
We now know that certain types of cancer are caused by
我们现在知道 某些类型的癌症
misplaced epigenetic tags and
是由表观遗传标记错位引起的
scientists are now developing drugs that can silence the bad genes
科学家们现在正在开发药物
that were supposed to be turned off in the first place
可以使那些本不该表达的有害基因沉默
additionally until recently we thought
此外 直到最近 我们还以为
that genes were the end all
基因就是一切的尽头
and be all of who you got to be.
完全决定了你将成为什么样的人
They were your blueprint and you couldn’t escape them.
它们是你无法逃脱的命运
This outlook is not just kind of depressing and
这种观点不仅令人沮丧
also alludes to a yucky sort of social prejudice
还暗示了一种令人厌恶的社会偏见
because when you look at data
因为当您在不考虑社会条件和
without considering social and epigenetic factors
表观遗传因素的情况下查看数据时
it might look like people with less money are less intelligent
可能看起来像是钱少的人不那么聪明
So just like 15 years ago there were scientists saying things in public
所以就像15年前有科学家公然声称
mind you like some people just have good genes for intelligence
无意冒犯 有些人就是有对于智力的优良基因
and it just so happens that the poor people don’t all it’s so sad too bad poor people
恰好穷人就没有这种基因 太令人沮丧了 可怜的穷人
But you have bad genes
但是你有劣等基因
Well it turns out that that is not even a little bit true
但是一个人有劣等基因被证明是无稽之谈
Not only are there a huge variety of social factors
不仅有许多社会因素
that affect how well people do on intelligence tests
影响了人们在智力测试的表现
but a genetic trait is also, not just a product of genes
而且遗传特征不仅是基因的产物
it’s also a product of environment
还是环境的产物
any one person’s genome was determined by
任何人的基因组都是
any number of decisions made by any number of their ancestors.
由其祖先做出的许多决定所确定的
And right now you are making decisions
而现在 你正在做出的决定
that are going to affect people who are alive long after you were dead
将影响到你去世后很长一段时间的人
no pressure or anything and
不过也别因此觉得压力山大
so I’m glad you’ve watched this
我很高兴你看了这个视频
because when you and your clone are in your 60s
因为当你和你的克隆人在60岁时
And you sit down have lunch, and he brings his son and his son has a tattoo on his face
你们一起用餐 他带着脸上有刺青的儿子
He did not inherit that from you.
那可不是从你身上继承的
This is Hank Green from the Scishow. We hope you learned something.
我是科学秀的汉克格林 我们希望你有所收获

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视频概述

我们现在做的决定可能会影响下一代甚至几代

听录译者

收集自网络

翻译译者

Karasu

审核员

审核员SX

视频来源

https://www.youtube.com/watch?v=kp1bZEUgqVI

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