CRISPR could be responsible for a new era of genetically perfected plants, animals,
and even humans…but what the heck is it?
Hello imperfect humans, Trace here for DNews.
A few years ago, something called Clustered Regularly Interspaced Short Palindromic Repeats
or CRISPR burst onto 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 their kid's sex,
eye color, height, or 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 -- a palindrome is a mirrored set of characters
like racecar or noon (though DNA sequences only use 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 system like a "most-wanted poster!"
It would detect an attack, go to the "most wanted poster" section of their DNA, figure
out which virus was attacking, and 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 the process, 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 on the molecular level.
That's tiny.
After word 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 a few as 20 base-pairs, meaning scientists
could cut single genes out of a DNA strand.
After it’s cut, the strand self-repairs, disabling the gene.
But, if scientists inject replacement DNA it fills the space instead.
This allows us to swap in DNA wherever we like.
Want corn with genes to fight bacteria?
Cool.
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, though they'd not allowed
them to grow.
WTF China!?
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 the discovery
that had won him the Nobel Prize.
But because it is so simple, scientists are calling for ethical oversight, 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 super scary.
Wanna know more about how these Chinese scientists altered the human embryos?
Check out the video our very own genetically perfected couple Julia and Julian did over
here.