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Gene editing can now change an entire species -- forever
-
Not SyncedSo this is a talk about gene drives,
-
Not Syncedbut I'm going to start by
telling you a brief story. -
Not Synced20 years ago, a biologist
named Anthony James -
Not Syncedgot obsessed by the idea
of making mosquitos -
Not Syncedthat didn't transmit malaria.
-
Not SyncedIt was a great idea,
but pretty much a complete failure. -
Not SyncedFor one thing, it turned out to be
really hard -
Not Syncedto make a malaria resistant mosquito.
-
Not SyncedJames managed it, finally,
just a few years ago -
Not Syncedby adding some genes
that make it impossible -
Not Syncedfor the malaria gene
to survive inside the mosquito. -
Not SyncedBut that just created another problem.
-
Not SyncedNow that you've got malaria-resistant
mosquito, -
Not Syncedhow do you get it to replace
all the malaria-carrying mosquitos? -
Not SyncedThere are a couple options,
-
Not Syncedbut plan A was basically to breed up
a bunch of the new genetically-engineered mosquotos, -
Not Syncedrelease them into the wild,
-
Not Syncedand hope that they pass on their genes.
-
Not SyncedThe problem was that you'd
have to release -
Not Syncedliterally 10x the number of native
mosquitos to work. -
Not SyncedSo in a village with 10,000 mosquitos,
-
Not Syncedyou release an extra 100,000.
-
Not SyncedAs you might guess, this was not
a very popular strategy -
Not Syncedwith the villagers.
-
Not Synced(Laughter)
-
Not SyncedThen, last January, Anthony James
got an email -
Not Syncedfrom a biologist named
Ethan Bier. -
Not SyncedBier said that he and his grad student,
Valentino Gantz, -
Not Syncedhad stumbled on a tool that could not only
guarentee -
Not Syncedthat a particular gene trait
would not be inherited, -
Not Syncedbut that it would spread
incredibly quickly. -
Not SyncedIf they were right, it would basically
solve the problem -
Not Syncedthat he and James had been
working on for 20 years. -
Not SyncedAs a test, they engineered
two mosquitos -
Not Syncedto carry the anti-malaria gene
-
Not Syncedand also this new tool,
a gene drive, -
Not Syncedwhich I'll explain in a minute.
-
Not SyncedFinally, they set it up so that
any mosquitos -
Not Syncedthat had inherited the
anti-malaria gene -
Not Syncedwouldn't have the usual white eyes,
but would instead have red eyes. -
Not SyncedThat was pretty much just
for convenience -
Not Syncedso they could tell just at a glance
which was which. -
Not SyncedSo they took their two
anti-malarial, red eye mosquitos -
Not Syncedand put them in a box with 30
ordinary white-eyed ones -
Not Syncedand let them breed.
-
Not SyncedIn two generations,
those had produced 38,000 grandchildren. -
Not SyncedThat is not the surprising part.
-
Not SyncedThis is the surprising part:
-
Not Syncedgiven that you started with just
two red-eyed mosquitos -
Not Syncedand 30 white-eyed ones,
-
Not Syncedyou expect mostly white-eyed
descendents. -
Not SyncedInstead, when James opened the box,
-
Not Syncedall 38,000 mosquitos had red eyes.
-
Not SyncedWhen I asked Ethan Bier
about this moment, -
Not Syncedhe became so excited, tht he was
literally shouting into the phone. -
Not SyncedThat's because getting only
red-eyed mosquitos -
Not Syncedviolates a rule that is the
absolute cornerstone of biology, -
Not SyncedMendelian genetics.
-
Not SyncedI'll keep this quick, but Mendelian genetics
says when a male and female mate, -
Not Syncedtheir baby inherits half of its
DNA from each parent. -
Not SyncedSo if our original mosquito was aa
and our new mosquito is aB, -
Not Syncedwhere B is the anti-malarial gene,
-
Not Syncedthe babies should come out
in four permutations: -
Not Syncedaa, aB, aa and Ba.
-
Not SyncedInstead, with the new gene drive,
-
Not Syncedthey all came out aB.
-
Not SyncedBiologically, that shouldn't
even be possible. -
Not SyncedSo what happened?
-
Not SyncedThe first thing that happened
was the arrival -
Not Syncedof a gene-editing tool
known as CRISPR in 2012. -
Not SyncedMany of you have probably heard
about CRISPR, -
Not Syncedso I'll just say briefly that CRISPR
is a tool that allows researchers -
Not Syncedto edit genes very precisely,
easily and quickly. -
Not SyncedIt does this by harnessing a mechanism
that already existed in bacteria. -
Not SyncedBasically, there's a protein
that acts like a scissors -
Not Syncedand cuts the DNA,
-
Not Syncedand there's an RNA molecule
that directs the scissors -
Not Syncedto any point on the genome you want.
-
Not SyncedThe result is basically a word processor
of genes. -
Not SyncedYou can take an entire gene out,
put one in, -
Not Syncedor even edit just a single letter
within a gene. -
Not SyncedAnd you can do it in nearly any species.
-
Not SyncedOkay, remember how I said
that gene drives -
Not Syncedoriginally had two problems?
-
Not SyncedThe first is that it was hard
to engineer a mosquito -
Not Syncedto be malaria resistant.
-
Not SyncedThat's basically gone now,
thanks to CRISPR. -
Not SyncedBut the other problem was
logistical. -
Not SyncedHow do you get your trait to spread?
-
Not SyncedThis is where it gets clever.
-
Not SyncedA couple years ago, a biologist
at Harvard named Kevin Esvelt -
Not Syncedwondered what would happen
if you made it so that -
Not SyncedCRISPR inserted not only
your new gene, -
Not Syncedbut also the machinery
that does the cutting and pasting. -
Not SyncedIn other words, what if CRISPR
also copy and pasted itself. -
Not SyncedYou'd end up with a perpetual
motion machine for gene editing. -
Not SyncedAnd that's exactly what happened.
-
Not SyncedThis CRISPR gene drive
that Esvelt created -
Not Syncednot only guarantees that a trait
will get passed on, -
Not Syncedbut if its used in the germline cell,
-
Not Syncedit will automatically copy and paste
your new gene -
Not Syncedinto both chromosomes of every
single individual. -
Not SyncedIt's like a global search and replace,
-
Not Syncedor in science terms,
-
Not Syncedit makes a heterozygous trait
homozygous. -
Not SyncedSo, what does this mean?
-
Not SyncedFor one thing, it means we have
a very powerful, -
Not Syncedbut also somewhat alarming new tool.
-
Not SyncedUp until now, the fact that gene drives
didn't work very well -
Not Syncedwas actually kind of a relief.
-
Not SyncedNormally when we mess around
with an organisms's genes, -
Not Syncedwe make that thing less evolutionarily fit.
-
Not SyncedSo biologists can make all the mutant
fruit flies they want -
Not Syncedwithout worrying about it.
-
Not SyncedIf some escape, natural selection
just takes care of it. -
Not SyncedWhat's remarkable and powerful
and frightening about gene drives -
Not Syncedis that that will no longer be true.
-
Not SyncedAssuming that your trait does not
have a big evolutionary handicap, -
Not Syncedlike a mosquito that can't fly,
-
Not Syncedthe CRISPR-based gene drive
will spread the change relentlessly -
Not Synceduntil it is in every single individual
in the population. -
Not SyncedNow, it isn't easy to make
a gene drive that works that well, -
Not Syncedbut James and Esvelt think
that we can. -
Not SyncedThe good news is that this opens
the door to some remarkable things. -
Not SyncedIf you put an anti-malarial gene drive
in just 1 percent -
Not Syncedof anopheles mosquitos,
the species that transmits malaria. -
Not SyncedResearchers estimate that it would
spread to the entire population -
Not Syncedin a year.
-
Not SyncedSo in a year, you could virtually
eliminate malaria. -
Not SyncedIn practice, we're still a few years out
from being able to do that, -
Not Syncedbut sitll, a 1,000 children a day
die of malaria. -
Not SyncedIn a year, that number could be
almost zero. -
Not SyncedThe same goes for dengue fever,
chicken genuang (?), yellow fever. -
Not SyncedAnd it gets better.
-
Not SyncedSay you want to get rid
of an invasive species, -
Not Syncedlike get Asian Carp out of
The Great Lakes. -
Not SyncedAll you have to do is release
a gene drive -
Not Syncedthat makes the fish produce
only male offspring. -
Not SyncedIn a few generations, there'll be
no females left, no more carp. -
Not SyncedIn theory, this means that we
could restore hundreds -
Not Syncedof native species that have been
pushed to the brink. -
Not SyncedOkay, that's the good news,
-
Not Syncedthis is the bad news.
-
Not SyncedGene drives are so effective,
-
Not Syncedthat even an accidental release
could change an entire species, -
Not Syncedand often very quickly.
-
Not SyncedAnthony James took the precautions.
-
Not SyncedHe breed his mosquitos in
a bio-containment lab -
Not Syncedand he also used a species
that's not native to the US -
Not Syncedso that even if some did escape,
-
Not Syncedthey'd just die off,
-
Not Syncedthere'd be nothing for them
to mate with. -
Not SyncedBut it's also true that if
a dozen Asian Carp -
Not Syncedwith the all-male gene drive accidentally
got carried from The Great Lakes -
Not Syncedback to Asia,
-
Not Syncedthey could potentially wipe out
the native Asian Carp population. -
Not SyncedAnd that's not so unlikely, given
how connected our world is. -
Not SyncedIn fact, it's why we have
an invasive species problem. -
Not SyncedAnd that's fish.
-
Not SyncedThings like mosquitos and fruit flies,
there's literally no way to contain them. -
Not SyncedThey cross borders and oceans
all the time.
- Title:
- Gene editing can now change an entire species -- forever
- Speaker:
- Jennifer Kahn
- Description:
-
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 12:25
Brian Greene edited English subtitles for Gene editing can now change an entire species -- forever | ||
Brian Greene edited English subtitles for Gene editing can now change an entire species -- forever | ||
Brian Greene edited English subtitles for Gene editing can now change an entire species -- forever | ||
Brian Greene approved English subtitles for Gene editing can now change an entire species -- forever | ||
Brian Greene edited English subtitles for Gene editing can now change an entire species -- forever | ||
Brian Greene edited English subtitles for Gene editing can now change an entire species -- forever | ||
Brian Greene edited English subtitles for Gene editing can now change an entire species -- forever | ||
Brian Greene edited English subtitles for Gene editing can now change an entire species -- forever |
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