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CRISPR是什么?它是如何对DNA进行编辑的?

What is CRISPR & How Could It Edit Your DNA?

CRISPR能开启全新的时代
CRISPR could be responsible for a new era
它能打造基因完美的植物 动物
of genetically perfected plants, animals,
甚至是人 但它到底是什么?
and even humans…but what the heck is it?
你好 不完美的人 欢迎收看DNews
Hello imperfect humans, Trace here for DNews.
几年前 “规律成簇的间隔短回文重复”
A few years ago, something called Clustered Regularly Interspaced Short Palindromic Repeats
即CRISPR 横空出世 它太有效了
or CRISPR burst into the scene. It worked so well
科学家开始对它的使用发表伦理声明
scientists began issuing ethical statements about its use.
CRISPR对DNA链的剪切
CRISPR cuts DNA strands with
精确简单 前所未有
unprecedented accuracy and simplicity,
利用它 遗传学家能随心所欲地
allowing geneticists to directly edit any of
改造地球上任何生物
Earth’s organisms however they like.
CRISPR能用于设计无病生物
CRISPR could be used to engineer disease-free organisms,
培育高产庄稼
formulate high-yield crops,
甚至治愈人类基因缺陷和遗传疾病
or even cure genetic and hereditary human conditions.
当然 理论上
Of course, it could theoretically
父母也能用它选择孩子的
also be used to let parents pick
性别 眼睛颜色 身高 等等
their kid’s sex, eye color, height, whatever.
总之 正如一位诺贝尔奖得主
In the end, CRISPR is, as one Nobel scientist
对《独立报》所说
said to the Independent
CRISPR的简单高效让人“瞠目结舌”
“jaw-dropping” in its efficiency and simplicity.
一切源于上世纪80年代末
It all began in the late 80s,when some
一些日本科学家研究细菌DNA时
Japanese scientists were looking at bacterial DNA.
发现了重复回文结构
They spotted repeated palindromic patterns.
回文是一组镜像符号
Palindrome is a mirrored set of characters
比如“racecar” “noon”就是回文
like racecar or noon
对DNA而言 只有A C T G四个符号
though DNA only uses A,C,T, or G.
本世纪初 科学家意识到这些重复序列是
In the 2000s, scientists realized these repeating characters were
古老的细菌免疫系统的一部分
part of an ancient bacterial immune system
回文结构能框定入侵病毒的DNA
The palindromes were framing the DNA of viral invaders!
细菌免疫系统把这段病毒DNA看作
This viral DNA is used by bacteria’s immune systems
“头号通缉令”
like a “most-wanted poster”.
免疫系统侦测病毒攻击
It would detect an attack,
找到病毒DNA中的“头号通缉”对象
go look at the “most wanted poster” section of their DNA,
鉴别入侵病毒种类
figure out which virus was attacking,
接着 召唤RNA守卫者进行反击
and then create an RNA defender to fight back.
RNA知道了敌人是谁
Now that the RNA knew what to attack .
还要有反击的方法
It needed a way to do so.
这时Cas9上场了
Which is where Cas9 comes in.
Cas9 即CRISPR关联蛋白9
CAS9 or CRISPR associated protein 9
是一种能解开并切断DNA的酶
is an enzyme that unwinds DNA and cuts it up.
关键是 这种剪切不仅适用于病毒DNA
Now, the trick is, that cutting process works with more than just viral DNA.
科学家一旦弄清了整个过程
Once scientists figured out how this process worked,
就试图将其用于
they learned how to use it
对任意DNA序列的剪切和替换
to cut out and replace any DNA sequence.
我知道这有点难
I know it’s confusing,
请把CRISPR看成我们的免疫系统
but think of it like our own immune system
RNA就像抗体 锁定入侵者
the RNA are like antibodies, tagging the invaders,
Cas9则像白细胞 将入侵者消灭
and the Cas9 eliminates them like our white blood cells do,
区别在于 人类是细胞水平
except instead of the cellular level,
而细菌是更小的分子水平 那是微观世界
it’s even smaller on the molecular level. It’s tiny.
研究一发布 各国科学家开始
After work got out, scientists everywhere began to
制备各自的RNA靶标
make their own RNA targets,
用Cas9包装 再放出去剪切DNA
wrap them in CAS9 and send them out to cut DNA.
就像我们自己的RNA军队
Like our own private RNA army.
CRISPR/Cas9如此精确
CRISPR/Cas9 is so accurate.
能识别仅有20个碱基的序列
It can recognize as few as 20 base-pairs,
意味着科学家能从DNA上截取单个基因
meaning scientists could cut single genes out of a DNA strand.
DNA链被剪切后 会自我修复残缺基因
After the strand was cut, it will self-repair disabling gene.
但科学家可注射替换DNA 填补空缺
But, if scientists inject replacement DNA, that will fill the space instead.
这样 我们就能在任何位置交换DNA
This allows us to swap in DNA wherever we like.
想要抗菌玉米? 酷!你能做到
You want corn with genes to fight bacteria? Cool! You can do that.
想要发光鱼?
Want fish that glow?
抓一段夜光藻的DNA扔进去
Grab some DNA from phosphorescent algae and toss it in there.
这个技术简单到可怕
This technique is so simple, it’s scary.
它为普及基因工程铺平了道路
It’s paving the way for widespread genetic engineering,
并引发媒体狂热报道
and it’s kicked off a media frenzy.
正如中国宣布开展人类胚胎
Like when Chinese authorities announced
基因编辑时 引起的关注
they’d edited human embryos,
尽管中国不允许这种胚胎长大
although they’d not allowe them to grow.
克雷格·梅洛是2006年诺贝尔
Craig Mello, is the co-Laureate of the 2006
医学奖共同得主之一
Nobel Prize for medicine and
他告诉《独立报》
he told The Independent,
“这是基础科学的一次胜利”
“It’s a triumph of basic science,” and
并宣称这比他的诺奖级发现还重要
claimed it was even more important than his discovery that had won him the Nobel Prize.
因为CRISPR如此简单
But because it is so simple,
科学家们呼吁各地开展伦理监督
scientists are calling for ethical oversight all over the place,
要让科学获得“公众支持”
and the need to align science with “public support.”
CRISPR/Cas9并非完美
Now, CRISPR/Cas9 isn’t perfect,
有时它会锚定并剪切DNA上的错误区段
sometimes the process will target the wrong section of DNA and cut there,
但发表在《自然》上的新论文
but a new paper in Nature describes how scientists
描述了科学家如何改造Cas9酶
altered the CAS9 enzyme
将“脱靶突变降低到检测限以下”
reducing “off-target mutations to undetectable levels.”
所以 他们成功让CRISPR变得完美
So, they improved on evolution, and now it’s perfect.
也更加可怕 感谢收看今天的DNews
And even more scary. Thanks for watching DNews today.
关于中国科学家如何改造
Do you wanna know more about these Chinese scientists
人类胚胎 想知道更多吗?
and how they altered human embryos?
请看我们的专题视频
check out the video that we did on that.
朱丽亚和朱利安是遗传学上的完美夫妻
Julia and Julian are genetically perfected couple.
请看
Checked it out over here.
DNA剪切酶被称为核酸酶
DNA cutting enzyme called a nuclease
可以注入细胞 在特定位置打断DNA
can be put into a cell that breaks the DNA at a specific place
去除错误或不想要的基因
and takes out the faulty or unwanted gene
当DNA链重组回去时
The DNA can use a synthetic sequence
可利用合成序列取代错误序列
that replaces the faulty one as the strands are put back together
关于CRISPR你怎么看?
What do you think about CRISPR?
吓坏了?棒极了?
Freak out? Is it awesome?
告诉我们你的看法
Let us know the comments.
请每天锁定收看DNews
Keep coming back here to DNews every day
要订阅哦 下次见
Make sure you subscribe. I’ll see you next time.

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视频概述

CRISPR是什么?它是如何编程DNA的?

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收集自网络

翻译译者

jm

审核员

审核团HN

视频来源

https://www.youtube.com/watch?v=SyAo51IYgUw

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