How Does CRISPR Work?

CRISPR is a gene editing technology based on how bacteria protect themselves from viruses. Learn how it works in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/life/genetic/crispr-gene-editing.htm

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff, Lauren Vogel bomb Here. Mutants are cool, right,
X men, teenage mutant ninja turtles, and superheroes across comic
books and films wow us with the special powers that
have been derived from their genetic mutations. However, these fictional

(00:23):
genetic mutations are kind of hard to come by. You
have to have been bitten by a radioactive spider or
exposed to some weird substance. But what if doing genetic
modifications wasn't just easy, but fast and cheap too. We're
a long way from creating superheroes, but a new technology
called crisper is making editing the genes of life forms

(00:46):
like crops, livestock, and pests a lot easier. Short for clustered,
regularly interspaced, short palindromic repeats, a crisper makes it possible
for us to move genes from any living thing into
another one, altering DNA for generations to come. It allows

(01:06):
us to cut away genes that are doing terrible things,
like those that cause disease, and replace them with segments
of DNA that are innocuous, Or we could replace innocuous
segments of DNA with genes that make corn or cattle
more disease resistant, lessening the need to spray or administer
antifungals or antibiotics. We might make yeast or algae colonies

(01:29):
that are really good at producing biofuel that we could
use to offset our dependence on fossil fuels. While crisper
technology is pretty awesome, humans genetically modifying different organisms is
nothing new. On the low tech side. We've been selectively
breeding crops for a long time. Owen farmers stumbled on
a particularly juicy orange or brightly colored tomato, they preserved

(01:53):
those desirable genes by collecting seeds or graphs from that plant.
But in recent ears, we've kicked biotechnology up a notch.
In the early two thousands, scientists figured out how to
use enzymes called zinc finger nucleases to delete and replace
specific genes in a variety of organisms. These zinc finger enzymes, however,

(02:15):
were expensive, hard to make, and the success rate was
not optimal. So while the technology to edit jeanes was there,
it wasn't until crisper came along that the idea of
deliberately changing in organism's DNA felt within grasp. The first
in road toward crisper technology appeared in a journal article

(02:37):
where scientists reported having found short, repeating segments of DNA
in equal I bacteria. This type of pattern in bacterial
DNA is unusual, so they parked up when they noticed
it and named the phenomenon crisper. Over time, scientists started
seeing this pattern in many different types of bacteria, but
there is still no hypothesis for what it was and

(03:00):
why it was there. But in two thousand five, a
search in a DNA database showed that the repeating segments
in bacteria matched DNA from viruses. But why would bacteria
have harbored away virus DNA? A scientist Eugene Conan hypothesized
that when bacteria survive a virus attack, they cut up

(03:22):
the virus into small pieces and store some of the
virus DNA in their own genome so that they can
later recognize and attack the virus if they happen to
meet it again. They're basically storing a picture of the
virus in their back pocket so that they can recognize
the bad guy if he ever shows his face again,
a remarkable defense mechanism of the bacterial immune system. The

(03:45):
Conan's hypothesis was right. If that virus hits again, the
bacteria manufacture special assassins. These assassins can read the DNA
sequence of any virus DNA they run into, recognize it
if it matches the information they've stored in their DNA,
and if they do, they'll trap it and chop it up.
It's as if the bacteria has created very specific, very

(04:08):
smart scissors. This discovery was pretty cool, but not as
cool as what University of California Berkeley scientist Jennifer Dowdna
thought to do with the information. She has since won
the Nobel Prize in Chemistry along with the Manuel Sharpontier
for their work on crisper A. Dowdna suggested that scientists

(04:30):
could use crisper as a tool to help them edit genes.
If they equipped the bacteria with a segment of DNA
that is known to be bad, say a gene that
causes heart failure, they could send the bacteria in to
seek out the bad gene, where the bacteria would find
it and clip it out, and then we could take
advantage of the natural repair mechanism in the bacterial cells

(04:51):
to throw a more desirable gene in its place. It worked,
and it kept working. A Crisper has stopped ANSWER cells
from multiplying, made cells impervious to HIV, helped us create
disease resistant wheat and rice, and countless other advances in
Scientists even attempted to use the technology on non viable

(05:14):
human embryos, but in only a few cases did Crisper
make the right cuts to the DNA. But this begs
the question do we even want to use it on embryos?
Should we be allowed to? Who will regulate the use
of Crisper. These questions are very much still unsettled, and

(05:34):
we're still a long ways from using Crisper on growing humans,
But the scientific community has these and other concerns firmly
in mind. International ethics panels have convened to discuss the issues,
and even DOWDNA herself warned against jumping into in womb
applications for CRISPER anytime soon, given the great risks and

(05:55):
unknown consequences of editing a human embryos genetic code. For now,
Crisper is contained mostly to laboratory experiments that are doing
much less potentially sinister things like attempting to engineer spicy tomatoes.
A decalf neated coffee beans, and cattle that won't grow horns,
meaning they won't have to have those horns removed later

(06:17):
in life as a safety measure. But all of that
is a matter for another episode. Today's episode is based
on the article how Crisper Jeane Editing works on how
stuff works dot com, written by Masa's Salida. Brain stuff
It's production of iHeart Radio in partnership with how stuff

(06:37):
Works dot Com and is produced by Tyler Clang. Four
more podcasts from my heart Radio. Visit the iHeart Radio app,
Apple Podcasts, or wherever you listen to your favorite shows.