CRISPR could be responsible for a new era
of genetically perfected plants, animals,
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.
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
scientists began issuing ethical statements about its use.
CRISPR cuts DNA strands with
unprecedented accuracy and simplicity,
allowing geneticists to directly edit any of
Earth’s organisms however they like.
CRISPR could be used to engineer disease-free organisms,
formulate high-yield crops,
or even cure genetic and hereditary human conditions.
Of course, it could theoretically
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.
In the end, CRISPR is, as one Nobel scientist
said to the Independent
“jaw-dropping” in its efficiency and simplicity.
It all began in the late 80s,when some
Japanese scientists were looking at bacterial DNA.
They spotted repeated palindromic patterns.
Palindrome is a mirrored set of characters
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.
In the 2000s, scientists realized these repeating characters were
part of an ancient bacterial immune system
The palindromes were framing the DNA of viral invaders!
This viral DNA is used by bacteria’s immune systems
like a “most-wanted poster”.
It would detect an attack,
go look at the “most wanted poster” section of their DNA,
figure out which virus was attacking,
and then create an RNA defender to fight back.
Now that the RNA knew what to attack .
It needed a way to do so.
Which is where Cas9 comes in.
CAS9 or CRISPR associated protein 9
is an enzyme that unwinds DNA and cuts it up.
Now, the trick is, that cutting process works with more than just viral DNA.
Once scientists figured out how this process worked,
they learned how to use it
to cut out and replace any DNA sequence.
I know it’s confusing,
but think of it like our own immune system
the RNA are like antibodies, tagging the invaders,
and the Cas9 eliminates them like our white blood cells do,
except instead of the cellular level,
it’s even smaller on the molecular level. It’s tiny.
After work got out, scientists everywhere began to
make their own RNA targets,
wrap them in CAS9 and send them out to cut DNA.
Like our own private RNA army.
CRISPR/Cas9 is so accurate.
It can recognize as few as 20 base-pairs,
meaning scientists could cut single genes out of a DNA strand.
After the strand was cut, it will self-repair disabling gene.
But, if scientists inject replacement DNA, that will fill the space instead.
This allows us to swap in DNA wherever we like.
You want corn with genes to fight bacteria? Cool! You can do that.
Want fish that glow?
Grab some DNA from phosphorescent algae and toss it in there.
This technique is so simple, it’s scary.
It’s paving the way for widespread genetic engineering,
and it’s kicked off a media frenzy.
Like when Chinese authorities announced
they’d edited human embryos,
although they’d not allowe them to grow.
Craig Mello, is the co-Laureate of the 2006
Nobel Prize for medicine and
he told The Independent,
“It’s a triumph of basic science,” and
claimed it was even more important than his discovery that had won him the Nobel Prize.
But because it is so simple,
scientists are calling for ethical oversight all over the place,
and the need to align science with “public support.”
Now, CRISPR/Cas9 isn’t perfect,
sometimes the process will target the wrong section of DNA and cut there,
but a new paper in Nature describes how scientists
altered the CAS9 enzyme
reducing “off-target mutations to undetectable levels.”
So, they improved on evolution, and now it’s perfect.
And even more scary. Thanks for watching DNews today.
Do you wanna know more about these Chinese scientists
and how they altered human embryos?
check out the video that we did on that.
Julia and Julian are genetically perfected couple.
Checked it out over here.
DNA cutting enzyme called a nuclease
can be put into a cell that breaks the DNA at a specific place
and takes out the faulty or unwanted gene
The DNA can use a synthetic sequence
that replaces the faulty one as the strands are put back together
What do you think about CRISPR?
Freak out? Is it awesome?
Let us know the comments.
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